Datasheet EPL_14 Datasheet

PL FUEL SYSTEM 14 - 1

FUEL SYSTEM

CONTENTS

page page

FUEL DELIVERY SYSTEM ................. 3

FUEL INJECTION SYSTEM ................ 21

GENERAL INFORMATION

INDEX

page page

GENERAL INFORMATION

FUEL REQUIREMENTS ................... 1

GENERAL INFORMATION

INTRODUCTION

Throughout this group, references may be made to
a particular vehicle by letter or number designation.
A chart showing the breakdown of these designations
is included in the Introduction Section at the front of
this service manual.

The Evaporation Control System, is also considered
part of the fuel system. The system reduces the emis­sion of fuel vapor into the atmosphere.

The description and function of the Evaporation
Control System is found in Group 25 of this manual.

FUEL REQUIREMENTS

Your vehicle was designed to meet all emission reg­ulations and provide excellent fuel economy when
using high quality unleaded gasoline.

Use unleaded gasolines having a minimum posted
octane of 87.

If your vehicle develops occasional light spark
knock (ping) at low engine speeds this is not harm­ful. However; continued heavy knock at high speeds
can cause damage and should be reported to your
dealer immediately. Engine damage as a result of
heavy knock operation may not be covered by the
new vehicle warranty.

In addition to using unleaded gasoline with the
proper octane rating, those that contain detergents,
corrosion and stability additives are recommended.
Using gasolines that have these additives will help
improve fuel economy, reduce emissions, and main­tain vehicle performance.

GENERAL INFORMATION .................. 1

GASOLINE/OXYGENATE BLENDS ........... 1

INTRODUCTION ........................ 1

Poor quality gasoline can cause problems such as
hard starting, stalling, and stumble. If you experi­ence these problems, try another brand of gasoline
before considering service for the vehicle.

GASOLINE/OXYGENATE BLENDS

Some fuel suppliers blend unleaded gasoline with
materials that contain oxygen such as alcohol, MTBE
(Methyl Tertiary Butyl Ether) and ETBE (Ethyl Ter­tiary Butyl Ether). Oxygenates are required in some
areas of the country during winter months to reduce
carbon monoxide emissions. The type and amount of
oxygenate used in the blend is important.

The following are generally used in gasoline
blends:

Ethanol - (Ethyl or Grain Alcohol) properly
blended, is used as a mixture of 10 percent ethanol
and 90 percent gasoline. Gasoline blended with etha­nol may be used in your vehicle.

MTBE/ETBE - Gasoline and MTBE (Methyl Ter­tiary Butyl Ether) blends are a mixture of unleaded
gasoline and up to 15 percent MTBE. Gasoline and
ETBE (Ethyl Tertiary Butyl Ether) are blends of gas­oline and up to 17 percent ETBE. Gasoline blended
with MTBE or ETBE may be used in your vehicle.

Methanol - Methanol (Methyl or Wood Alcohol) is
used in a variety of concentrations blended with
unleaded gasoline. You may encounter fuels contain­ing 3 percent or more methanol along with other
alcohols called cosolvents.

DO NOT USE GASOLINES CONTAINING
METHANOL.

14 - 2 FUEL SYSTEM PL

GENERAL INFORMATION (Continued)

Use of methanol/gasoline blends may result in
starting and driveability problems and damage criti­cal fuel system components.

Problems that are the result of using methanol/
gasoline blends are not the responsibility of Chrysler
Corporation and may not be covered by the vehicle
warranty.

Reformulated Gasoline

Many areas of the country are requiring the use of
cleaner-burning fuel referred to as Reformulated
Gasoline . Reformulated gasolines are specially
blended to reduce vehicle emissions and improve air
quality.

Chrysler Corporation strongly supports the use of
reformulated gasolines whenever available. Although
your vehicle was designed to provide optimum perfor­mance and lowest emissions operating on high qual­ity unleaded gasoline, it will perform equally well
and produce even lower emissions when operating on
reformulated gasoline.

Materials Added to Fuel

Indiscriminate use of fuel system cleaning agents
should be avoided. Many of these materials intended
for gum and varnish removal may contain active sol­vents of similar ingredients that can be harmful to
fuel system gasket and diaphragm materials.

FUEL FILTER/PRESSUREREGULATOR FUEL LEVEL SENSORFUEL RESERVOIR INLET STRAINER FLOAT

PL FUEL SYSTEM 14 - 3

FUEL DELIVERY SYSTEM

INDEX

page page

DESCRIPTION AND OPERATION

ELECTRIC FUEL PUMP ................... 4

FUEL DELIVERY SYSTEM ................. 3

FUEL FILTER/FUEL PRESSURE REGULATOR . . 4

FUEL GAUGE SENDING UNIT .............. 4

FUEL INJECTORS ....................... 5

FUEL PUMP MODULE .................... 3

FUEL RAIL ............................. 4

FUEL TANK ............................ 4

PRESSURE-VACUUM FILLER CAP .......... 5

QUICK-CONNECT FITTINGS ............... 5

ROLLOVER VALVES ..................... 6

DIAGNOSIS AND TESTING

FUEL INJECTORS ....................... 8

FUEL LEVEL SENSOR .................... 8

FUEL PUMP PRESSURE TEST ............. 6

SERVICE PROCEDURES

DRAINING FUEL TANK .................. 10

FUEL SYSTEM PRESSURE RELEASE

PROCEDURE ........................ 10

DESCRIPTION AND OPERATION

FUEL DELIVERY SYSTEM

The fuel delivery system consists of: the electric
fuel pump, fuel filter/fuel pressure regulator, fuel
tubes/lines/hoses, fuel rail, fuel injectors, fuel tank,
accelerator pedal and throttle cable.

A fuel return system is used on all models (all
engines). Fuel is returned through the fuel pump
module and back into the fuel tank through the fuel
filter/fuel pressure regulator. A separate fuel return
line from the engine to the tank is no longer used
with any engine.

The fuel tank assembly consists of: the fuel tank,
filler tube, fuel gauge sending unit/electric fuel pump
module, a pressure relief/rollover valve and a pres­sure-vacuum filler cap.

Also to be considered part of the fuel system is the
evaporation control system. This is designed to
reduce the emission of fuel vapors into the atmo­sphere. The description and function of the Evapora­tive Control System is found in Group 25, Emission
Control Systems.

HOSES AND CLAMPS ................... 10

QUICK-CONNECT FITTINGS .............. 11

REMOVAL AND INSTALLATION

ACCELERATOR PEDAL .................. 18

AUTOMATIC SHUTDOWN RELAY .......... 12

FUEL FILLER NECK ..................... 17

FUEL FILLER TUBE ROLLOVER VALVE ...... 17

FUEL FILTER / PRESSURE REGULATOR .... 13

FUEL INJECTORS ...................... 15

FUEL LEVEL SENSOR ................... 14

FUEL PUMP INLET STRAINER ............ 14

FUEL PUMP MODULE ................... 12

FUEL PUMP RELAY ..................... 12

FUEL TANK ........................... 16

THROTTLE CABLE—AUTOMATIC

TRANSMISSION ...................... 19

THROTTLE CABLE—MANUAL

TRANSMISSION ...................... 18

SPECIFICATIONS

TORQUE SPECIFICATION ................ 20

• Electric fuel pump

• Fuel pump reservoir

• Inlet strainer

• Fuel filter/pressure regulator

• Fuel gauge sending unit

• Fuel supply line connection

The inlet strainer, fuel pressure regulator and fuel
level sensor are the only serviceable items. If the fuel
pump requires service, replace the fuel pump module.

FUEL PUMP MODULE

The fuel pump module is installed in the top of the
fuel tank (Fig. 1). The fuel pump module contains the
following:

Fig. 1 Fuel Pump Module

INTERNAL FUEL FILTER FUEL FLOW TO FUEL INJEC-TORSFUEL FILTER/FUEL PRES-SURE REGULATORO-RINGSEXCESS FUEL BACK TOTANKFUEL INLETCALIBRATED SPRINGSRUBBER GROM-MET AT PUMPMODULELOCKINGTAB

14 - 4 FUEL SYSTEM PL

DESCRIPTION AND OPERATION (Continued)

ELECTRIC FUEL PUMP

The electric fuel pump is located in and is part of
the fuel pump module. It is a positive displacement,
gerotor type, immersible pump with a permanent
magnet electric motor. The fuel pump module is sus­pended in fuel in the fuel tank. The pump draws fuel
through a strainer and pushes it through the motor
to the outlet. The pump contains a check valves. The
valve, in the pump outlet, maintains pump pressure
during engine off conditions. The fuel pump relay
provides voltage to the fuel pump.

The fuel pump has a maximum deadheaded pres­sure output of approximately 880 kPa (130 psi). The
regulator adjusts fuel system pressure to approxi­mately 338 kPa (49 psi).

FUEL GAUGE SENDING UNIT

The fuel gauge sending unit (fuel level sensor) is
attached to the side of the fuel pump module. The
sending unit consists of a float, an arm, and a vari­able resistor (track). The resistor track is used to
send electrical signals to the Powertrain Control
Module (PCM) for fuel gauge operation and for OBD
II emission requirements.

For fuel gauge operation: As fuel level
increases, the float and arm move up. This decreases
the sending unit resistance, causing the fuel gauge to
read full. As fuel level decreases, the float and arm
move down. This increases the sending unit resis­tance causing the fuel gauge to read empty.

After this fuel level signal is sent to the PCM, the
PCM will transmit the data across the CCD bus cir­cuits to the instrument panel. Here it is translated
into the appropriate fuel gauge level reading.

For OBD II emission requirements: The voltage
signal is sent from the resistor track to the PCM to
indicate fuel level. The purpose of this feature is to
prevent a false setting of misfire and fuel system
monitor trouble codes. This is if the fuel level in the
tank is less than approximately 15 percent of its
rated capacity.

FUEL FILTER/FUEL PRESSURE REGULATOR

A combination fuel filter and fuel pressure regula­tor is used on all gas powered engines. It is located
on the top of the fuel pump module. A separate frame
mounted fuel filter is not used.

Fuel Pressure Regulator Operation: The pres­sure regulator is a mechanical device that is cali­brated to maintain fuel system operating pressure of
approximately 338 kPa (49 psi) at the fuel injectors.

It contains a diaphragm, calibrated springs and a
fuel return valve. The internal fuel filter (Fig. 2) is
also part of the assembly.

Fuel is supplied to the filter/regulator by the elec­tric fuel pump through an opening tube at the bot­tom of filter/regulator.

The fuel pump module contains a check valve to
maintain some fuel pressure when the engine is not
operating. This will help to start the engine.

If fuel pressure at the pressure regulator exceeds
approximately 49 psi, an internal diaphragm closes
and excess fuel pressure is routed back into the tank
through the pressure regulator. A separate fuel
return line is not used with any gas powered engine.

Fig. 2 Side View—Filter/Regulator

FUEL TANK

All models pass a full 360 degree rollover test
without fuel leakage. To accomplish this, fuel and
vapor flow controls are required for all fuel tank con­nections.

All models have a pressure relief/rollover valve
mounted on the top of the fuel pump module.

An evaporative control system is used to reduce
emissions of fuel vapors into atmosphere by evapora­tion and to reduce unburned hydrocarbons emitted
by vehicle engine. When fuel evaporates from fuel
tank, vapors pass through vent hoses or tubes to a
charcoal canister. The vapors are temporarily held in
the canister. When the engine is running, the vapors
are drawn into intake manifold. Refer to Group 25,
Emission Control System for additional information.

FUEL RAIL

The fuel rail supplies the necessary fuel to each
individual fuel injector and is mounted to the intake
manifold (Fig. 3). The fuel pressure regulator is no

FUEL RAIL TEST PORT

FUEL INJECTOR NOZZLETOP (FUEL ENTRY)

FUEL INJEC-TORS

FUEL RAIL

INTAKE MANI-

FOLD

PL FUEL SYSTEM 14 - 5

DESCRIPTION AND OPERATION (Continued)

longer mounted to the fuel rail on any engine. It is
now located on the fuel tank mounted fuel pump
module. Refer to Fuel Filter/Fuel Pressure Regulator
in the Fuel Delivery System section of this group for
information. The fuel rail is not repairable.

Fig. 5 Fuel Injector Location—Typical

Fig. 3 Fuel Rail—Typical

FUEL INJECTORS

The fuel injectors are 12 ohm electrical solenoids
(Fig. 4). The injector contains a pintle that closes off
an orifice at the nozzle end. When electric current is
supplied to the injector, the armature and needle
move a short distance against a spring, allowing fuel
to flow out the orifice. Because the fuel is under high
pressure, a fine spray is developed in the shape of a
hollow cone. The spraying action atomizes the fuel,
adding it to the air entering the combustion chamber.
The injectors are positioned in the intake manifold.

release for all gas caps is between 0.97 and 2.0 kPa
(0.14 and 0.29 psi). The cap must be replaced by a
similar unit if replacement is necessary.

WARNING: REMOVE FILLER CAP TO RELIEVE
TANK PRESSURE BEFORE REMOVING OR REPAIR­ING FUEL SYSTEM COMPONENTS.

Fuel Tank Capacity

Vehicle Liters U.S.Gallons
PL 47 12.5

Fig. 4 Fuel Injector

The injectors are positioned in the intake manifold
with the nozzle ends directly above the intake valve
port (Fig. 5).

PRESSURE-VACUUM FILLER CAP

The loss of any fuel or vapor out of the filler neck
is prevented by the use of a safety filler cap. The cap
will release pressure only under significant pressure
of 10.9 to 13.45 kPa (1.58 to 1.95 psi). The vacuum

NOTE: Nominal refill capacities are shown. A varia­tion may be observed from vehicle due to manufac­turing tolerance and refill procedure.

QUICK-CONNECT FITTINGS

Different types of quick-connect fittings are used to
attach various fuel system components. These are: a
single-tab type, a two-tab type or a plastic retainer
ring type. Some are equipped with safety latch clips.
Refer to the Removal/Installation section for more
information.

CAUTION: The interior components (o-rings, spac­ers) of quick-connect fitting are not serviced sepa­rately. Do not attempt to repair damaged fittings or
fuel lines/tubes. If repair is necessary, replace the
complete fuel tube assembly.

Fuel tubes connect fuel system components with
plastic quick-connect fuel fittings. The fitting con­tains non-serviceable O-ring seals (Fig. 6).

CAUTION: Quick-connect fittings are not serviced
separately. Do not attempt to repair damaged quick­connect fittings or fuel tubes. Replace the complete
fuel tube/quick-connect fitting assembly.

CASING WINDOW RETAINER TABNIPPLEO RINGSWINDOWRETAINER “EAR”

FUEL RAIL

IGNITION COILSELECTRICAL CON-NECTOR

TEST PORTFUEL INJEC-TORSSPARK PLUGINSULATOR

FUEL PRESSURE GAUGEC-4799-B

FUEL RAIL TEST PORT

SPARK PLUG

FUEL RAIL

CABLE

14 - 6 FUEL SYSTEM PL

DESCRIPTION AND OPERATION (Continued)

Fig. 7 Fuel Pressure Test Port—Typical

Fig. 6 Plastic Quick-Connect Fittings

The quick-connect fitting consists of the O-rings,
retainer and casing (Fig. 6). When the fuel tube
enters the fitting, the retainer locks the shoulder of
the nipple in place and the O-rings seal the tube.

ROLLOVER VALVES

All PL vehicles have two rollover valves. One in
the fuel filler tube and the other on the top of the
fuel tank. The valves prevent fuel flow through the
fuel tank vent valve hoses should the vehicle rollover.

DIAGNOSIS AND TESTING

FUEL PUMP PRESSURE TEST

The fuel system operates at approximately 338 kPa
(49 psi). Check fuel system pressure at the test port
on the fuel rail (Fig. 7).

(1) Remove cap from fuel pressure test port on fuel
rail.

(2) Connect Fuel Pressure Gauge C-4799B to test
port (Fig. 8).

CAUTION: When using the ASD Fuel System Test,
the ASD relay and fuel pump relay remain energized
for 7 minutes or until the test is stopped, or until
the ignition switch is turned to the Off position.

Fig. 8 Checking Fuel Pressure at Intake Manifold—

Typical

• If the gauge reading equals 338 kPa (49 PSI)
further testing is not required. If pressure is not cor­rect, record the pressure.

• If fuel pressure is below specifications, refer to
the Fuel Pressure Diagnosis Chart (Fig. 9).

• If fuel pressure is above specifications (54 psi or
higher) check for a kinked or restricted fuel supply
line. If the supply line is not kinked or restricted,
replace the Fuel Filter/Pressure Regulator.

(3) Place the ignition key in the ON position.
Using the DRB scan tool, access ASD Fuel System
Test. The ASD Fuel System Test will activate the fuel
pump and pressurize the system.

IF CHASSIS FUEL LINE ISNOT RESTRICTED.REPLACE FILTER/REGULA-TOR

RESTRICTEDREPLACE INLET STRAINER NOT RESTRICTEDINCORRECTLY OPERATING FUELFILTER/REGULATOR OR FUEL PUMPREPLACE FUEL FILTER/REG-ULATOR

FUEL PRESSURE BELOW SPECIFICA-

CHECK FOR RESTRICTED FUEL PUMP

TIONS

INLET STRAINER

FUEL PRESSURE ABOVE SPECIFICATIONSRESTRICTION IN CHASSIS FUEL SUP-

PLY LINE. CHECK FOR KINKED OR

PLUGGED FUEL SUPPLY LINE

PL FUEL SYSTEM 14 - 7

DIAGNOSIS AND TESTING (Continued)

Fig. 9 Fuel Pressure Diagnosis Chart

14 - 8 FUEL SYSTEM PL

DIAGNOSIS AND TESTING (Continued)

FUEL LEVEL SENSOR

This procedure tests the resistance of the level sen­sor itself. It does not test the level sensor circuit.
Refer to Group 8W - Wiring Diagrams for circuit
identification.

The level sensor is a variable resistor. Its resis­tance changes with the amount of fuel in the tank.
The float arm attached to the sensor moves as the
fuel level changes. To test the level sensor, connect
an ohmmeter across the sensor signal and sensor
ground terminals of the fuel pump module connector
(Fig. 10). Move the float lever to the positions shown
in the resistance chart (Fig. 10). Record the resis­tance at each point. Replace the level sensor if the
resistance is not within specifications.

FUEL INJECTORS

For fuel injector diagnosis, refer to the Fuel Injec­tor Diagnosis charts. For poor fuel economy diagnosis
or engine miss, also refer to Transmission Driveplate
in this section

Fig. 10 Level Sensor Diagnosis

DO PRELIMINARY VISUALINSPECTION OF IGNITIONWIRES AND SPARK PLUGS,AND CHECK FOR VACUUMLEAKS. CONNECT DRB SCAN TOOL TOVEHICLE. ACCESS THE AUTO-MATIC INJECTOR KILL TEST ONTHE SYSTEM TEST SCREEN.PERFORM THE AUTOMATICINJECTOR KILL TEST TO ISO-LATE SUSPECT INJECTOR(S). REMOVE INTAKEMANIFOLD PLENUM.REFER TO SERVICEPROCEDURES SEC-TION. USING AN OHMMETER, TEST THEINJECTOR RESISTANCE ACROSSTHE INJECTOR TERMINALS WITHTHE INJECTOR CONNECTORREMOVED.

REPLACE THE INJECTOR. YESPLACE A 12 VOLT TEST LAMPACROSS THE INJECTOR ELECTRI-CAL CONNECTOR TERMINALS.OBSERVE THE TEST LAMP WHILECRANKING THE ENGINE.TEST LAMP FLASHESNOCHECK POWER FEED ANDGROUND CIRCUITSBETWEEN PCM AND THEINJECTOR CONNECTOR.REFER TO WIRING DIA-GRAMS FOR COLOR CODESAND PIN TERMINAL NUM-BERS.CIRCUITS OK?YESTEST THE ENGINE CON-TROL SYSTEM WITH THEDRB SCAN TOOL.NOREPAIR OR REPLACE THEWIRING HARNESS AS NEC-ESSARY.YESCIRCUIT IS OK. CHECK FORFUEL DELIVERY AT SUS-PECT INJECTOR BY REMOV-ING THE INJECTOR FROMTHE RAIL AND OBSERVINGFOR FUEL AND/ORRESTRICTIONS I THE RAILOR INJECTOR FUEL INLET.REFER TO FUEL INJECTORREMOVAL AND INSTALLA-TION IN THE SERVICE PRO-CEDURES SECTION OF THISGROUP.YESNOREPLACE INJECTOR IFVISUALLY PLUGGED ATINJECTOR FUEL INLET.CLEAN FUEL PASSAGE IFVISUALLY PLUGGED ORRESTRICTED.FUEL PRESENT AT INJEC-TOR?YESWITH INJECTOR REMOVEDFROM THE FUEL RAIL, CON-NECT A 12V SOURCE TOONE TERMINAL ON THEINJECTOR CONNECTORAND A GROUND WIRE TOTHE OTHER TERMINAL. THEINJECTOR SHOULD “CLICK”EACH TIME THE GROUNDWIRE IS CONNECTED ANDDISCONNECTED TO THETERMINAL.DOES INJECTOR “CLICK”?NOREPLACE INJECTOR.YESINJECTOR IS OK.

PL FUEL SYSTEM 14 - 9

NO

APPROXIMATELY 12.0
OHMS RESISTANCE

AT 20°C (68°F)

DIAGNOSIS AND TESTING (Continued)

.

FUEL INJECTOR DIAGNOSIS

14 - 10 FUEL SYSTEM PL

SERVICE PROCEDURES

FUEL SYSTEM PRESSURE RELEASE PROCEDURE

WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE SERVICING FUEL SYSTEM COMPONENTS.
SERVICE VEHICLES IN WELL VENTILATED AREAS
AND AVOID IGNITION SOURCES. NEVER SMOKE
WHILE SERVICING THE VEHICLE.

(1) Disconnect negative cable from battery.

(2) Remove fuel filler cap.

(3) Remove the protective cap from the fuel pres­sure test port on the fuel rail (Fig. 11).

IGNITION COILSELECTRICAL CON-NECTOR

TEST PORTFUEL INJEC-TORSSPARK PLUGINSULATOR

SPARK PLUG

FUEL RAIL

CABLE

FUEL RAILHOSEC-4799-1ATTACHEDTO TESTPORT

DRAINING FUEL TANK

WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE SERVICING FUEL SYSTEM COMPONENTS.
SERVICE VEHICLES IN WELL VENTILATED AREAS
AND AVOID IGNITION SOURCES. NEVER SMOKE
WHILE SERVICING THE VEHICLE.

(1) Remove fuel filler cap.
(2) Perform the Fuel System Pressure Release pro-

cedure.

(3) Disconnect negative cable from battery.
(4) Raise vehicle on hoist.

(5) Remove quick connect cap from drain port. The
drain port is located on rear top of fuel tank. Push a
siphon hose into the drain port (Fig. 13).

(6) Drain fuel tank into holding tank or a properly
labeled Gasoline safety container.

Fig. 11 Fuel Pressure Test Port—Typical

(4) Place the open end of fuel pressure release
hose, tool number C-4799-1, into an approved gaso­line container. Connect the other end of hose
C-4799-1 to the fuel pressure test port (Fig. 12). Fuel
pressure will bleed off through the hose into the gas­oline container. Fuel gauge C-4799-A contains hose
C-4799-1.

Fig. 12 Releasing Fuel Pressure

Fig. 13 Drain Port Location

HOSES AND CLAMPS

Inspect all hose connections (clamps and quick con­nect fittings) for completeness and leaks. Replace
cracked, scuffed, or swelled hoses. Replace hoses that
rub against other vehicle components or show sign of
wear.

Fuel injected vehicles use specially constructed
hoses. When replacing hoses, only use hoses marked
EFM/EFI.

When installing hoses, ensure that they are routed
away from contact with other vehicle components
that could rub against them and cause failure. Avoid
contact with clamps or other components that cause
abrasions or scuffing. Ensure that rubber hoses are
properly routed and avoid heat sources.

The hose clamps have rolled edges to prevent the
clamp from cutting into the hose. Only use clamps
that are original equipment or equivalent. Other
types of clamps may cut into the hoses and cause
high pressure fuel leaks. Tighten hose clamps to 1
N·m (10 in. lbs.) torque.

PL FUEL SYSTEM 14 - 11

SERVICE PROCEDURES (Continued)

QUICK-CONNECT FITTINGS

REMOVAL

When disconnecting a quick-connect fitting, the

retainer will remain on the fuel tube nipple.

WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE DISCONNECTING A QUICK-CONNECT FIT­TINGS. REFER TO THE FUEL PRESSURE RELEASE
PROCEDURE.

(1) Disconnect negative cable from battery.

(2) Perform Fuel Pressure Release Procedure.
Refer to the Fuel Pressure Release Procedure in this
section.

(3) Squeeze retainer tabs together and pull fuel
tube/quick-connect fitting assembly off of fuel tube
nipple. The retainer will remain on fuel tube.

INSTALLATION

CAUTION: Never install a quick-connect fitting
without the retainer being either on the fuel tube or
already in the quick-connect fitting. In either case,
ensure the retainer locks securely into the quick­connect fitting by firmly pulling on fuel tube and fit­ting to ensure it is secured.

CAUTION: When using the ASD Fuel System Test,
the Auto Shutdown (ASD) Relay remains energized
for either 7 minutes, until the test is stopped, or
until the ignition switch is turned to the Off posi­tion.

(5) Use the DRB scan tool ASD Fuel System Test

to pressurize the fuel system. Check for leaks.

PLASTIC RETAINER RING TYPE FITTING

This type of fitting can be identified by the use of a
full-round plastic retainer ring (Fig. 15) usually black
in color.

(1) Using a clean lint free cloth, clean the fuel tube

nipple and retainer.

(2) Prior to connecting the fitting to the fuel tube,
coat the fuel tube nipple with clean 30 weight engine
oil.

(3) Push the quick-connect fitting over the fuel
tube until the retainer seats and a click is heard.

(4) The plastic quick-connect fitting has windows
in the sides of the casing. When the fitting com­pletely attaches to the fuel tube, the retainer locking
ears and the fuel tube shoulder are visible in the
windows. If they are not visible, the retainer was not
properly installed (Fig. 14). Do not rely upon the

audible click to confirm a secure connection.

WINDOW TAB (2)EARSHOULDER (ON TUBE)

Fig. 15 Plastic Retainer Ring Type Fitting

CAUTION: The interior components (o-rings, spac­ers, retainers) of this type of quick-connect fitting
are not serviced separately. Do not attempt to repair
damaged fittings or fuel lines/tubes. If repair is nec­essary, replace the complete fuel tube assembly.

WARNING: THE FUEL SYSTEM IS UNDER A CON­STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING ANY FUEL SYSTEM HOSES,
FITTINGS OR LINES, THE FUEL SYSTEM PRES­SURE MUST BE RELEASED. REFER TO THE FUEL
SYSTEM PRESSURE RELEASE PROCEDURE IN
THIS GROUP.

Fig. 14 Plastic Quick-Connect Fitting/Fuel Tube

Connection

DISCONNECTION/CONNECTION

(1) Disconnect negative battery cable from the bat-

tery.

BATTERY POSITIVEBATTERY GROUNDAIR CLEANERPCMPDCTCM

14 - 12 FUEL SYSTEM PL

SERVICE PROCEDURES (Continued)

(2) Perform the fuel pressure release procedure.
Refer to the Fuel Pressure Release Procedure in this
section.

(3) Clean the fitting of any foreign material before
disassembly.

(4) To release the fuel system component from the
quick-connect fitting, firmly push the fitting towards
the component being serviced while firmly pushing
the plastic retainer ring into the fitting (Fig. 15).
With the plastic ring depressed, pull the fitting from
the component. The plastic retainer ring must be

pressed squarely into the fitting body. If this
retainer is cocked during removal, it may be
difficult to disconnect fitting. Use an open-end
wrench on the shoulder of the plastic retainer
ring to aid in disconnection.

(5) After disconnection, the plastic retainer ring
will remain with the quick-connect fitting connector
body.

(6) Inspect fitting connector body, plastic retainer
ring and fuel system component for damage. Replace
as necessary.

(7) Prior to connecting the quick-connect fitting to
component being serviced, check condition of fitting
and component. Clean the parts with a lint-free
cloth. Lubricate them with clean engine oil.

(8) Insert the quick-connect fitting into the compo­nent being serviced until a click is felt.

(9) Verify a locked condition by firmly pulling on
fuel tube and fitting (15-30 lbs.).

(10) Connect negative battery cable to battery.

(11) Start engine and check for leaks.

REMOVAL AND INSTALLATION

AUTOMATIC SHUTDOWN RELAY

The relay is located in the Power Distribution Cen­ter (PDC) (Fig. 16). The PDC is located next to the
battery in the engine compartment. For the location
of the relay within the PDC, refer to the PDC cover
for location. Check electrical terminals for corrosion
and repair as necessary.

FUEL PUMP RELAY

The fuel pump relay is located in the PDC. The
inside top of the PDC cover has a label showing relay
and fuse location.

FUEL PUMP MODULE

REMOVAL

WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE SERVICING FUEL SYSTEM COMPONENTS.
SERVICE VEHICLES IN WELL VENTILATED AREAS

AND AVOID IGNITION SOURCES. NEVER SMOKE
WHILE SERVICING THE VEHICLE.

the Fuel Tank section of this group.

WARNING: THE FUEL RESERVOIR OF THE FUEL
PUMP MODULE DOES NOT EMPTY OUT WHEN THE
TANK IS DRAINED. THE FUEL IN THE RESERVOIR
WILL SPILL OUT WHEN THE MODULE IS
REMOVED.

depressing quick connect retainers with thumb and
fore finger.

lock to unlock.
fuel pump module, by pushing down on connector

retainer and pulling connector off of module.
tank. remove bolts from fuel tank straps.

module locknut (Fig. 18).
Discard old seal.

INSTALLATION

seal in position in the tank opening.
aligment tab on the underside of the fuel pump mod-

ule flange sits in the notch on the fuel tank.
ule.

Fig. 16 Power Distribution Center (PDC)

(1) Drain the fuel. Refer to Draining Fuel Tank in

(2) Disconnect fuel line from fuel pump module by

(3) Slide fuel pump module electrical connecter
(4) Disconnect the electrical connection from the

(5) Use a transmission jack to support the fuel
(6) Lower tank slightly.

(7) Use Special Tool 6856 to remove fuel pump
(8) Remove fuel pump and O-ring seal from tank.

(1) Wipe seal area of tank clean and place a new
(2) Position fuel pump in the tank. Make sure the

(3) Position the locknut over the fuel pump mod-

LOCKNUT

FUEL FILTER/PRESSURE REGULATORFUEL

SPECIAL TOOL 6856LOCKNUT

LINE

FUEL FILTER/PRESSURE REGULATOR

SPRING TABLOCATING SLOT

PL FUEL SYSTEM 14 - 13

REMOVAL AND INSTALLATION (Continued)

(2) Raise vehicle on hoist.

(3) Disconnect fuel supply line at the Filter/Regu­lator nipple (refer to Quick Connect Fittings in this
section).

(4) Depress locking spring tab on side of Fuel/Reg­ulator (Fig. 19) and rotate 90° counter-clockwise and
pull out.

NOTE: Make sure that the upper and lower O-rings
are on the Filter/Regulator assembly.

Fig. 17 Fuel Pump Module Removal

(4) Tighten the locknut using Special Tool 6856 to

55 N·m (40.5 ft. lbs.) (Fig. 18).

Fig. 18 Fuel Tank Locknut

CAUTION: Over tightening the pump lock ring may
result in a leak.

(5) Fill fuel tank. Check for leaks.

FUEL FILTER / PRESSURE REGULATOR

REMOVAL

WARNING: THE FUEL SYSTEM IS UNDER A CON­STANT PRESSURE, EVEN WITH ENGINE OFF.
BEFORE SERVICING THE FUEL FILTER/FUEL
PRESSURE REGULATOR, THE FUEL SYSTEM
PRESSURE MUST BE RELEASED.

Fig. 19 Locking Spring Tab

INSTALLATION

Lightly lubricate the O-rings with engine oil.

(1) Insert Filter/Regulator into the opening in the
fuel pump module, align the two hold down tabs with
the flange.

(2) While applying downward pressure, rotate the

FUEL FILTER/PRESSURE REGULATORSPRING TABLOCATING SLOT

Filter/Regulator clockwise until the the spring tab
engages the locating slot (Fig. 20).

(3) Connect the fuel line to the Filter/Regulator.

(4) Lower vehicle from hoist.

(1) Refer to Fuel System Pressure Release in the

Fuel Delivery System section of this group.

The fuel filter/fuel pressure regulator is located on
the top of fuel pump module. Fuel pump module
removal is not necessary.

Fig. 20 Spring Tab In Locating Slot

TABSINLET STRAINER

RETAINING TAB TANK SEALELECTRICAL CONNECTOR

WIRE TER-MINAL

LOCKINGFINGER

ELECTRICALCONNECTORBLUE LOCKING WEDGE

14 - 14 FUEL SYSTEM PL

REMOVAL AND INSTALLATION (Continued)

FUEL PUMP INLET STRAINER

REMOVAL

(1) Remove fuel pump module. Refer to Fuel Pump
Module Removal in this section.

(2) Using a thin straight blade screwdriver, pry
back the locking tabs on fuel pump reservoir and
remove the strainer (Fig. 21).

(3) Remove strainer O-ring from the fuel pump
reservoir body.

(4) Remove any contaminants in the fuel tank by
washing the inside of the fuel tank.

Fig. 22 Fuel Pump/Level Sensor Electrical

Connector

Fig. 21 Inlet Strainer Removal

INSTALLATION

(1) Lubricate the strainer O-ring with clean engine
oil.

(2) Insert strainer O-ring into outlet of strainer so
that it sits evenly on the step inside the outlet.

(3) Push strainer onto the inlet of the fuel pump
reservoir body. Make sure the locking tabs on the
reservoir body lock over the locking tangs on the
strainer.

(4) Install fuel pump module. Refer to Fuel Pump
Module Installation in this section.

FUEL LEVEL SENSOR

REMOVAL

Remove fuel pump module. Refer to Fuel Pump
Module in this section.

(1) Depress retaining tab and remove the fuel
pump/level sensor connector from the bottom of the
fuel pump module electrical connector (Fig. 22).

(2) Pull off blue locking wedge (Fig. 23).

(3) Using a small screwdriver lift locking finger
away from terminal and push terminal out of connec­tor (Fig. 24).

Fig. 23 Wire Terminal Locking Wedge

Fig. 24 Wire Terminal Locking Finger

REAR VIEW OF LEVEL SEN-SOR LEVEL SENSORWRAP WIRES INGROOVECHANNEL FOR LEVEL SEN-SOR

WIRE TER-MINAL

LOCKINGFINGER

FUEL LEVEL SEN-SORCHANNEL FOR LEVEL SEN-SOR

FUEL SUP-

PLY LINE

IGNITIONCOILFUEL LINE QUICKCONNECTSFUELINJECTOR

FUEL RAIL

PL FUEL SYSTEM 14 - 15

REMOVAL AND INSTALLATION (Continued)

(4) Push level sensor signal and ground terminals
out of the connector (Fig. 25).

Fig. 25 Removing Wires From Connector

(5) Insert a screwdriver between the fuel pump
module and the top of the level sensor housing (Fig.

26). Push level sensor down slightly.

(7) Slide level sensor out of installation channel in

module.

INSTALLATION

(1) Insert level sensor wires into bottom of opening

in module.

(2) Wrap wires into groove in back of level sensor

(Fig. 26).

(3) While feeding wires into guide grooves, slide
level sensor up into channel until it snaps into place
(Fig. 27). Ensure tab at bottom of sensor locks in
place.

(4) Install level sensor wires in connector. Push
the wires up through the connector and then pull
them down until they lock in place. Ensure signal
and ground wires are installed in the correct posi­tion.

(5) Install locking wedge on connector.

(6) Push connector up into bottom of fuel pump
module electrical connector.

(7) Install fuel pump module. Refer to Fuel Pump
Module in this section.

FUEL INJECTORS

Fig. 26 Loosening Level Sensor

(6) Slide level sensor wires through opening fuel

pump module (Fig. 27).

REMOVAL

(1) Disconnect negative cable from battery.

(2) Release fuel system pressure. Refer to Fuel
System Pressure Release procedure in this section.

(3) Disconnect fuel supply tube from rail. Refer to
Quick-Connect Fittings in the Fuel Delivery section
of this group.

(4) Disconnect electrical connectors from fuel injec­tors (Fig. 28).

Fig. 27 Level Sensor Removal/Installation

Fig. 28 Fuel Rail and Injectors

14 - 16 FUEL SYSTEM PL

REMOVAL AND INSTALLATION (Continued)

RETAINER

FUEL INJECTOR NOZZLETOP (FUEL ENTRY)

FUEL INJECTOR

FUEL RAIL

(5) Remove fuel rail mounting screws.
(6) Lift rail off of intake manifold. Cover the fuel

injector openings in the intake manifold.

(7) Remove fuel injector retainer (Fig. 29).

Fig. 29 Fuel Injector Retainer

(8) Pull injector out of fuel rail. Replace fuel injec-

tor O-rings (Fig. 30).

FUEL TANKDRAINFUEL PUMP MOD-ULEHEAT SHIELD

FUEL TANK

ELECTRICAL CON-

REMOVAL

NECTOR

FUEL LINE

(1) Perform fuel system pressure release.

Fig. 31 Fuel Tank

(2) Drain fuel tank. Refer to Draining Fuel Tank
in this section (Fig. 31).

(3) Raise vehicle on hoist.

Fig. 30 Fuel Injector O-Rings

INSTALLATION

(1) Apply a light coating of clean engine oil to the

upper O-ring.

(2) Install injector in cup on fuel rail.
(3) Install retaining clip.
(4) Apply a light coating of clean engine oil to the

O-ring on the nozzle end of each injector.

(5) Insert fuel injector nozzles into openings in
intake manifold. Seat the injectors in place. Tighten
fuel rail mounting screws to 22.5 N·m 6 3 N·m
(200630 in. lbs.).

(6) Attach electrical connectors to fuel injectors.

(7) Connect fuel supply tube to fuel rail. Refer to
Quick Connect Fittings in the Fuel Delivery Section
of this Group.

WARNING: WRAP SHOP TOWELS AROUND
HOSES TO CATCH ANY GASOLINE SPILLAGE.

(4) Disconnect fuel pump module electrical connec-

tor (Fig. 32).

Fig. 32 Fuel Pump Module Electrical Connector

(5) Disconnect the fuel tube from Fuel Filter/Reg­ulator. Refer to Quick Connect Fittings in the Fuel
Delivery section of this group.

(6) Support tank with transmission jack. Loosen
tank mounting straps and lower tank slightly.

(7) Disconnect fuel filler tube and filler vent tube
from filler hose at fuel tank (Fig. 33).

FUEL FILL VAPORTUBE FUEL FILLER TUBE FUEL TANK DRAINVAPOR TUBE TO CANISTERVAPOR TUBE TO TANK

FUEL FILLER NECKQUARTER PANEL

PL FUEL SYSTEM 14 - 17

REMOVAL AND INSTALLATION (Continued)

Fig. 33 Fuel Filler Tube and Vent Tubes

(8) Disconnect fuel filler vapor relief tube from tee
connecting it to the tank vapor relief tube and EVAP
canister tube.

(9) Disconnect vapor line from Evap canister tube.

(10) Remove tank mounting straps and lower tank.

INSTALLATION

(1) Position fuel tank on transmission jack.

(2) Raise tank into position. Connect fuel filler
tube tank inlet nipple.

(3) Tighten fuel tank strap nuts to 23 N·m (250 in.
lbs.) torque. Remove transmission jack. Ensure
straps are not twisted or bent.

(4) Attach fuel tubes to pump module and chassis
fuel tube. Refer to Quick Connect Fittings in the Fuel
Delivery section of this Group.

(5) Connect fuel vapor tube to tee, then to Evap
canister tube.

(6) Attach electrical connector to fuel pump mod­ule.

(7) Lower vehicle.

(8) Fill fuel tank, install filler cap, and connect
battery cable.

FUELFILLERTUBE

ROLLOVER VALVE

VAPOR TUBE
TO EVAP CAN-

Fig. 34 Fuel Filler Neck

(4) Disconnect fuel filler tube from fuel tank.

Remove filler neck.

INSTALLATION

(1) Reverse for installation.

FUEL FILLER TUBE ROLLOVER VALVE

REMOVAL

The rollover valve is mounted in the fuel filler tube

(Fig. 35).

ISTER

CAUTION: When using the ASD Fuel System Test,
the Auto Shutdown (ASD) Relay remains energized
for either 7 minutes, until the test is stopped, or
until the ignition switch is turned to the Off posi­tion.

(9) Use the DRB scan tool ASD Fuel System Test
to pressurize the fuel system. Check for leaks.

FUEL FILLER NECK

REMOVAL

(1) Loosen fuel filler tube cap.

(2) Remove fuel filler neck screws (Fig. 34).

(3) Disconnect fuel fill vapor tube.

Fig. 35 Fuel Filler Tube Rollover Valve

(1) To release fuel tank pressure, remove the fuel

filler tube cap.

(2) Disconnect vapor tube from rollover valve.
(3) Using a straight screwdriver, pry the valve out

of the grommet in the fuel filler tube.

INSTALLATION

(1) Apply a light coating of power steering fluid to

the grommet.

(2) Install valve in grommet.

GROMMET CABLEPEDAL SHAFTAND BRACKETSEALDASHPANELCABLE ASSEM-BLY

RETAINER CLIP GROMMETCABLE ASSEM-BLY CABLERETAINERDASH PANELGROMMET

MOUNTING TABTHROTTLE CONTROLSHIELDMOUNTING SCREW

14 - 18 FUEL SYSTEM PL

REMOVAL AND INSTALLATION (Continued)

(3) Attach vapor tube to valve.

(4) Install fuel filler tube cap.

ACCELERATOR PEDAL

CAUTION: When servicing the accelerator pedal,
throttle cable or speed control cable, do not dam­age or kink the core wire inside the cable sheath­ing.

REMOVAL

(1) Working from the engine compartment, remove
the throttle control shield.

(2) Hold the throttle body throttle lever in the
wide open position. Remove the throttle cable from
the throttle body cam.

(3) From inside the vehicle, hold up the pedal and
remove the cable retainer and throttle cable from the
upper end of the pedal shaft (Fig. 36) and (Fig. 37).

(4) Working from the engine compartment, remove
nuts from accelerator pedal attaching studs (Fig. 36).
Remove assembly from vehicle.

INSTALLATION

(1) Position accelerator pedal assembly on dash
panel. Install retaining nuts. Tighten retaining nuts
to 12 N·m (105 in. lbs.) torque.

(2) From inside the vehicle, hold up the pedal and
install the throttle cable and cable retainer in the
upper end of the pedal shaft.

(3) From the engine compartment, hold the throt­tle body lever in the wide open position and install
the throttle cable. Install the throttle control shield.

THROTTLE CABLE—MANUAL TRANSMISSION

REMOVAL

(1) Remove throttle control shield (Fig. 38).

Fig. 36 Accelerator Pedal and Throttle Cable—Front

View

Fig. 37 Accelerator Pedal and Throttle Cable—Rear

View

Fig. 38 Throttle Control Shield

(2) Working from the engine compartment, remove
the throttle cable from the throttle body lever (Fig.

39) and (Fig. 40).

(3) Compress the retaining tabs on the cable and
slide cable out of bracket.

(4) From inside the vehicle, hold the accelerator
pedal up and remove the cable retainer and cable
from upper end of pedal shaft (Fig. 36) and (Fig. 37).

(5) Remove retainer clip from throttle cable and
grommet at the dash panel.

(6) From the engine compartment, pull the throttle
cable out of the dash panel grommet. The grommet
should remain in the dash panel.

SPEED CONTROLCABLE THROTTLECABLETHROTTLELEVER

SPEED CON-TROL CABLE THROTTLECABLETRANSMISSIONKICKDOWNCABLE

TABSCABLECLASP

PL FUEL SYSTEM 14 - 19

REMOVAL AND INSTALLATION (Continued)

CLASP

TABSCABLE

Fig. 39 Throttle Cable Attachment to Throttle Body

Fig. 40 Disconnecting Throttle Cable

INSTALLATION

(1) From the engine compartment, push the hous-

ing end fitting into the dash panel grommet.

(2) Install cable housing (throttle body end) into

the cable mounting bracket on the engine.

(3) From inside the vehicle, hold up pedal and feed
throttle cable core wire through hole in upper end of
the pedal shaft. Install cable retainer.

(4) Install cable retainer clip.

(5) From the engine compartment, rotate the
throttle lever forward to the wide open position and
install cable clasp (Fig. 40).

(6) Install throttle control shield (Fig. 38). Tighten
screw to 5.6 N·m (50 in. lbs.).

THROTTLE CABLE—AUTOMATIC TRANSMISSION

REMOVAL

(1) Remove throttle control shield (Fig. 38).

(2) Working from the engine compartment, remove
throttle cable from throttle body cam (Fig. 41) and
(Fig. 42).

Fig. 41 Throttle Body Cables Attachment to Throttle

Body

Fig. 42 Disconnecting Throttle Cable

(3) Compress the retaining tabs on the cable and

slide cable out of bracket.

(4) From inside the vehicle, hold the throttle pedal
up and remove the cable retainer and cable from
upper end of pedal shaft (Fig. 36) and (Fig. 37).

(5) Remove retainer clip from throttle cable and
grommet at the dash panel.

(6) From the engine compartment, pull the throttle
cable out of the dash panel grommet. The grommet
should remain in the dash panel.

INSTALLATION

(1) From the engine compartment, push the hous­ing end fitting into the dash panel grommet.

(2) Install cable housing (throttle body end) into
the cable mounting bracket on the engine.

(3) From inside the vehicle, hold up pedal and feed
throttle cable core wire through hole in upper end of
the pedal shaft. Install cable retainer (Fig. 37).

(4) Install cable retainer clip.

14 - 20 FUEL SYSTEM PL

REMOVAL AND INSTALLATION (Continued)

(5) From the engine compartment, rotate the
throttle lever forward to the wide open position and
install cable clasp (Fig. 42).

(6) Install throttle ontrol shield (Fig. 38). Tighten
to 5.6 N·m (50 in. lbs.).

SPECIFICATIONS

TORQUE SPECIFICATION

DESCRIPTION TORQUE

Accelerator Pedal to Dash Nuts . 12 N·m (105 in. lbs.)

Fuel Pump Module Locknut ....55N·m(40ft.lbs.)

Fuel Tank Strap Bolts .......23N·m(250 in. lbs.)

Fuel Rail Bolts .............23N·m(195 in. lbs.)

Ignition Coil Mounting Bolts . . . 11 N·m (95 in. lbs.)

Intake Manifold Bolts ........11N·m(95in.lbs.)

Throttle Control Shield .......5.6N·m(50in.lbs.)

PL FUEL SYSTEM 14 - 21

FUEL INJECTION SYSTEM

INDEX

page page

GENERAL INFORMATION

INTRODUCTION ....................... 22

MODES OF OPERATION ................. 22

DESCRIPTION AND OPERATION

AIR CONDITIONING CLUTCH RELAY—PCM

OUTPUT ............................ 33

AIR CONDITIONING PRESSURE

TRANSDUCER—PCM INPUT ............ 26

AUTOMATIC SHUTDOWN (ASD) SENSE—PCM

INPUT .............................. 26

AUTOMATIC SHUTDOWN RELAY—PCM

OUTPUT ............................ 33

BATTERY TEMPERATURE SENSOR—PCM

INPUT .............................. 26

BATTERY VOLTAGE—PCM INPUT .......... 26

BRAKE SWITCH—PCM INPUT ............. 26

CAMSHAFT POSITION SENSOR—PCM

INPUT .............................. 27

CHARGING SYSTEM INDICATOR LAMP—PCM

OUTPUT ............................ 33

CRANKSHAFT POSITION SENSOR—PCM

INPUT .............................. 27

DATA LINK CONNECTOR ................. 35

DUTY CYCLE EVAP PURGE SOLENOID—PCM

OUTPUT ............................ 34

ELECTRIC EGR TRANSDUCER—PCM

OUTPUT ............................ 34

ENGINE COOLANT TEMPERATURE SENSOR—

PCM INPUT ......................... 28

FUEL INJECTORS—PCM OUTPUT ......... 35

FUEL LEVEL SENSOR—PCM INPUT ........ 29

FUEL PUMP RELAY—PCM OUTPUT ........ 34

GENERATOR FIELD—PCM OUTPUT ........ 34

HEATED OXYGEN SENSOR (O2S SENSOR)—

PCM INPUT ......................... 29

IDLE AIR CONTROL MOTOR—PCM OUTPUT . 34

IGNITION CIRCUIT SENSE—PCM INPUT .... 30

IGNITION COIL—PCM OUTPUT ............ 36

INTAKE AIR TEMPERATURE SENSOR—PCM

INPUT .............................. 30

KNOCK SENSOR—PCM INPUT ............ 31

MALFUNCTION INDICATOR (CHECK ENGINE)

LAMP—PCM OUTPUT ................. 36

MANIFOLD ABSOLUTE PRESSURE (MAP)

SENSOR—PCM INPUT ................. 31

PARK/NEUTRAL POSITION SWITCH—PCM

INPUT .............................. 32

POWER DISTRIBUTION CENTER .......... 25

POWER STEERING PRESSURE SWITCH—

PCM INPUT ......................... 31

POWERTRAIN CONTROL MODULE ......... 25

RADIATOR FAN CONTROL MODULE—PCM

OUTPUT ............................ 36

SCI RECEIVE—PCM INPUT ............... 32

SCI RECEIVE—PCM INPUT ............... 37

SENSOR RETURN—PCM INPUT ........... 31

SPEED CONTROL—PCM INPUT ........... 31

SPEED CONTROL—PCM INPUT ........... 37

SYSTEM DIAGNOSIS .................... 24

TACHOMETER—PCM OUTPUT ............ 37

THROTTLE POSITION SENSOR—PCM

INPUT .............................. 32

TORQUE CONVERTOR CLUTCH SOLENOID—

PCM OUTPUT ........................ 37

VEHICLE SPEED SENSOR—PCM INPUT .... 33

DIAGNOSIS AND TESTING

ASD AND FUEL PUMP RELAYS ............ 47

CAMSHAFT AND CRANKSHAFT POSITION

SENSOR ............................ 47

ENGINE COOLANT TEMPERATURE SENSOR . 48

HEATED OXYGEN SENSOR .............. 48

IDLE AIR CONTROL (IAC) MOTOR TEST ..... 48

KNOCK SENSOR ....................... 48

MANIFOLD ABSOLUTE PRESSURE (MAP)

SENSOR ............................ 48

THROTTLE BODY MINIMUM AIR FLOW ..... 49

THROTTLE POSITION SENSOR ........... 49

VEHICLE SPEED SENSOR ............... 50

VISUAL INSPECTION—DOHC ............. 42

VISUAL INSPECTION—SOHC ............. 37

REMOVAL AND INSTALLATION

AIR CLEANER ELEMENT ................. 56

CAMSHAFT POSITION SENSOR ........... 55

CRANKSHAFT POSITION SENSOR ......... 55

DOWNSTREAM HEATED OXYGEN SENSOR . 56
DUTY CYCLE EVAP PURGE SOLENOID

VALVE .............................. 54

ENGINE COOLANT TEMPERATURE SENSOR . 57

IDLE AIR CONTROL MOTOR .............. 53

KNOCK SENSOR ....................... 58

MAP/IAT SENSOR—DOHC ................ 54

MAP/IAT SENSOR—SOHC ................ 53

POWERTRAIN CONTROL MODULE (PCM) . . . 54
THROTTLE BODY—AUTOMATIC

TRANSMISSION ...................... 51

14 - 22 FUEL SYSTEM PL

SPECIFICATIONS (Continued)

THROTTLE BODY—MANUAL

TRANSMISSION ...................... 50

THROTTLE POSITION SENSOR (TPS) ...... 52

UPSTREAM HEATED OXYGEN SENSOR .... 55

VEHICLE SPEED SENSOR ............... 58

GENERAL INFORMATION

INTRODUCTION

All engines used in this section have a sequential
Multi-Port Electronic Fuel Injection system. The MPI
system is computer regulated and provides precise
air/fuel ratios for all driving conditions. The Power­train Control Module (PCM) operates the fuel injec­tion system.

The PCM regulates:

• Ignition timing

• Air/fuel ratio

• Emission control devices

• Cooling fan

• Charging system

• Idle speed

• Vehicle speed control

Various sensors provide the inputs necessary for
the PCM to correctly operate these systems. In addi­tion to the sensors, various switches also provide
inputs to the PCM.

All inputs to the PCM are converted into signals.
The PCM can adapt its programming to meet chang­ing operating conditions.

Fuel is injected into the intake port above the
intake valve in precise metered amounts through
electrically operated injectors. The PCM fires the
injectors in a specific sequence. Under most operat­ing conditions, the PCM maintains an air fuel ratio
of 14.7 parts air to 1 part fuel by constantly adjust­ing injector pulse width. Injector pulse width is the
length of time the injector is open.

The PCM adjusts injector pulse width by opening
and closing the ground path to the injector. Engine
RPM (speed) and manifold absolute pressure (air
density) are the primary inputs that determine injec­tor pulse width.

MODES OF OPERATION

As input signals to the PCM change, the PCM
adjusts its response to output devices. For example,
the PCM must calculate a different injector pulse
width and ignition timing for idle than it does for
Wide Open Throttle (WOT). There are several differ­ent modes of operation that determine how the PCM
responds to the various input signals.

There are two different areas of operation, OPEN
LOOP and CLOSED LOOP.

During OPEN LOOP modes the PCM receives
input signals and responds according to preset PCM

SPECIFICATIONS

TORQUE SPECIFICATIONS ............... 58

VECI LABEL ........................... 58

SPECIAL TOOLS

FUEL ................................ 59

programming. Inputs from the upstream and down­stream heated oxygen sensors are not monitored dur­ing OPEN LOOP modes, except for heated oxygen
sensor diagnostics (they are checked for shorted con­ditions at all times).

During CLOSED LOOP modes the PCM monitors
the inputs from the upstream and downstream
heated oxygen sensors. The upstream heated oxygen
sensor input tells the PCM if the calculated injector
pulse width resulted in the ideal air-fuel ratio of 14.7
to one. By monitoring the exhaust oxygen content
through the upstream heated oxygen sensor, the
PCM can fine tune injector pulse width. Fine tuning
injector pulse width allows the PCM to achieve opti­mum fuel economy combined with low emissions.

For the PCM to enter CLOSED LOOP operation,
the following must occur:

(1) Engine coolant temperature must be over 35°F.

• If the coolant is over 35° the PCM will wait 44

seconds.

• If the coolant is over 50°F the PCM will wait 38

seconds.

• If the coolant is over 167°F the PCM will wait

11 seconds.

(2) For other temperatures the PCM will interpo­late the correct waiting time.

(3) O2 sensor must read either greater than .745
volts or less than .1 volt.

(4) The multi-port fuel injection systems has the
following modes of operation:

• Ignition switch ON (Zero RPM)

• Engine start-up

• Engine warm-up

• Cruise

• Idle

• Acceleration

• Deceleration

• Wide Open Throttle

• Ignition switch OFF

(5) The engine start-up (crank), engine warm-up,
deceleration with fuel shutoff and wide open throttle
modes are OPEN LOOP modes. Under most operat­ing conditions, the acceleration, deceleration (with
A/C on), idle and cruise modes, with the engine at
operating temperature are CLOSED LOOP modes.

IGNITION SWITCH ON (ZERO RPM) MODE

When the ignition switch activates the fuel injec­tion system, the following actions occur:

PL FUEL SYSTEM 14 - 23

GENERAL INFORMATION (Continued)

• The PCM monitors the engine coolant tempera­ture sensor and throttle position sensor input. The
PCM determines basic fuel injector pulse width from
this input.

• The PCM determines atmospheric air pressure
from the MAP sensor input to modify injector pulse
width.

When the key is in the ON position and the engine
is not running (zero rpm), the Auto Shutdown (ASD)
and fuel pump relays de-energize after approximately
1 second. Therefore, battery voltage is not supplied to
the fuel pump, ignition coil, fuel injectors and heated
oxygen sensors.

ENGINE START-UP MODE

This is an OPEN LOOP mode. If the vehicle is in
park or neutral (automatic transaxles) or the clutch
pedal is depressed (manual transaxles) the ignition
switch energizes the starter relay. The following
actions occur when the starter motor is engaged.

• If the PCM receives the camshaft position sensor
and crankshaft position sensor signals, it energizes
the Auto Shutdown (ASD) and fuel pump relays. If
the PCM does not receive both signals within approx­imately one second, it will not energize the ASD
relay and fuel pump relay. The ASD and fuel pump
relays supply battery voltage to the fuel pump, fuel
injectors, ignition coil and heated oxygen sensors.

• The PCM energizes all four injectors (on the 69°
degree falling edge) for a calculated pulse width until
it determines crankshaft position from the camshaft
position sensor and crankshaft position sensor sig­nals. The PCM determines crankshaft position within
1 engine revolution.

• After determining crankshaft position, the PCM
begins energizing the injectors in sequence. It adjusts
injector pulse width and controls injector synchroni­zation by turning the individual ground paths to the
injectors On and Off.

• When the engine idles within 664 RPM of its
target RPM, the PCM compares current MAP sensor
value with the atmospheric pressure value received
during the Ignition Switch On (zero RPM) mode. If
the PCM does not detect a minimum difference
between the two values, it sets a MAP diagnostic
trouble code into memory.

Once the ASD and fuel pump relays have been
energized, the PCM determines injector pulse width
based on the following:

• Battery voltage

• Engine coolant temperature

• Engine RPM

• Intake air temperature (IAT)

• Throttle position

• The number of engine revolutions since cranking

was initiated

During Start-up the PCM maintains ignition tim-

ing at 9° BTDC.

ENGINE WARM-UP MODE

This is an OPEN LOOP mode. The following inputs

are received by the PCM:

• Engine coolant temperature

• Manifold Absolute Pressure (MAP)

• Intake air temperature (IAT)

• Crankshaft position (engine speed)

• Camshaft position

• Knock sensor

• Throttle position

• A/C switch

• Battery voltage

• Power steering pressure switch

• Vehicle speed

• Speed control

• Both O2 sensors

• All diagnostics

The PCM adjusts injector pulse width and controls
injector synchronization by turning the individual
ground paths to the injectors On and Off.

The PCM adjusts ignition timing and engine idle
speed. Engine idle speed is adjusted through the idle
air control motor.

CRUISE OR IDLE MODE

When the engine is at operating temperature this
is a CLOSED LOOP mode. During cruising or idle
the following inputs are received by the PCM:

• Intake air temperature

• Engine coolant temperature

• Manifold absolute pressure

• Crankshaft position (engine speed)

• Camshaft position

• Knock sensor

• Throttle position

• Exhaust gas oxygen content

• A/C control positions

• Power steering pressure switch

• Battery voltage

• Vehicle speed

The PCM adjusts injector pulse width and controls
injector synchronization by turning the individual
ground paths to the injectors On and Off.

The PCM adjusts engine idle speed and ignition
timing. The PCM adjusts the air/fuel ratio according
to the oxygen content in the exhaust gas (measured
by the upstream and downstream heated oxygen sen­sor).

The PCM monitors for engine misfire. During
active misfire and depending on the severity, the
PCM either continuously illuminates or flashes the
malfunction indicator lamp (Check Engine light on
instrument panel). Also, the PCM stores an engine
misfire DTC in memory.

14 - 24 FUEL SYSTEM PL

GENERAL INFORMATION (Continued)

The PCM performs several diagnostic routines.

They include:

• Oxygen sensor monitor

• Downstream heated oxygen sensor diagnostics

during open loop operation (except for shorted)

• Fuel system monitor

• EGR monitor

• Purge system monitor

• All inputs monitored for proper voltage range.

• All monitored components (refer to Group 25 for

On-Board Diagnostics).

The PCM compares the upstream and downstream
heated oxygen sensor inputs to measure catalytic
convertor efficiency. If the catalyst efficiency drops
below the minimum acceptable percentage, the PCM
stores a diagnostic trouble code in memory.

During certain idle conditions, the PCM may enter
a variable idle speed strategy. During variable idle
speed strategy the PCM adjusts engine speed based
on the following inputs.

• A/C sense

• Battery voltage

• Battery temperature

• Engine coolant temperature

• Engine run time

• Power steering pressure switch

• Vehicle mileage

ACCELERATION MODE

This is a CLOSED LOOP mode. The PCM recog­nizes an abrupt increase in Throttle Position sensor
output voltage or MAP sensor output voltage as a
demand for increased engine output and vehicle
acceleration. The PCM increases injector pulse width
in response to increased fuel demand.

DECELERATION MODE

This is a CLOSED LOOP mode. During decelera­tion the following inputs are received by the PCM:

• A/C pressure transducer

• A/C sense

• Battery voltage

• Intake air temperature

• Engine coolant temperature

• Crankshaft position (engine speed)

• Exhaust gas oxygen content (upstream heated

oxygen sensor)

• Knock sensor

• Manifold absolute pressure

• Power steering pressure switch

• Throttle position

• IAC motor control changes in respones to MAP

sensor feedback

The PCM may receive a closed throttle input from
the Throttle Position Sensor (TPS) when it senses an
abrupt decrease in manifold pressure. This indicates
a hard deceleration. In response, the PCM may
momentarily turn off the injectors. This helps
improve fuel economy, emissions and engine braking.

If decel fuel shutoff is detected, downstream oxy­gen sensor diagnostics is performed.

WIDE-OPEN-THROTTLE MODE

This is an OPEN LOOP mode. During wide-open­throttle operation, the following inputs are received
by the PCM:

• Intake air temperature

• Engine coolant temperature

• Engine speed

• Knock sensor

• Manifold absolute pressure

• Throttle position

When the PCM senses a wide-open-throttle condi­tion through the Throttle Position Sensor (TPS) it de­energizes the A/C compressor clutch relay. This
disables the air conditioning system.

The PCM does not monitor the heated oxygen sen­sor inputs during wide-open-throttle operation except
for downstream heated oxygen sensor and both
shorted diagnostics. The PCM adjusts injector pulse
width to supply a predetermined amount of addi­tional fuel.

IGNITION SWITCH OFF MODE

When the operator turns the ignition switch to the
OFF position, the following occurs:

• All outputs are turned off, unless 02 Heater
Monitor test is being run. Refer to Group 25,
On-Board Diagnostics.

• No inputs are monitored except for the heated
oxygen sensors. The PCM monitors the heating ele­ments in the oxygen sensors and then shuts down.

DESCRIPTION AND OPERATION

SYSTEM DIAGNOSIS

The PCM can test many of its own input and out­put circuits. If the PCM senses a fault in a major
system, the PCM stores a Diagnostic Trouble Code
(DTC) in memory.

Technicians can display stored DTC’s by two differ­ent methods.

For DTC information, refer to Group 25, Emission
Control Systems. See On-Board Diagnostics.

PL FUEL SYSTEM 14 - 25

DESCRIPTION AND OPERATION (Continued)

POWER DISTRIBUTION CENTER

POWER DISTRI-BUTION CEN-TER FUSESRELAYS

The power distribution center (PDC) is located next
to the battery (Fig. 1). The PDC contains the starter
relay, radiator fan relay, A/C compressor clutch relay,
auto shutdown relay, fuel pump relay and several
fuses.

Fig. 1 Power Distribution Center (PDC)

SPEED CON-TROL SERVO WINDSHIELDWASHER FLUIDBOTTLEPCMBATTERYPOWER DISTRI-BUTION CEN-TER

POWERTRAIN CONTROL MODULE

The Powertrain Control Module (PCM) is a digital
computer containing a microprocessor (Fig. 2). The
PCM receives input signals from various switches
and sensors that are referred to as PCM Inputs.
Based on these inputs, the PCM adjusts various
engine and vehicle operations through devices that
are referred to as PCM Outputs.

Fig. 2 Powertrain Control Module (PCM)

PCM Inputs:

• Air Conditioning Controls

• Battery Voltage

• Battery Temperature Sensor

• Brake Switch

• Camshaft Position Sensor

• Crankshaft Position Sensor

• Engine Coolant Temperature Sensor

• Fuel Level Sensor

• Ignition Switch

• Intake Air Temperature Sensor

• Knock Sensor

• Manifold Absolute Pressure (MAP) Sensor

• Oxygen Sensors

• Power Steering Pressure Switch

• SCI Receive

• Speed Control Switches

• Throttle Position Sensor

• Transmission Park/Neutral Switch (automatic

transmission)

• Vehicle Speed Sensor

PCM Outputs:

• Air Conditioning WOT Relay

• Auto Shutdown (ASD) Relay

• Charging Indicator Lamp

• Data Link Connector

• Duty Cycle EVAP Canister Purge Solenoid

• EGR Solenoid

• Fuel Injectors

• Fuel Pump Relay

• Generator Field

• Idle Air Control Motor

• Ignition Coils

• Malfunction Indicator (Check Engine) Lamp

• Radiator Fan Relay

• Speed Control Solenoids

• Tachometer

• Torque Convertor Clutch Solenoid

Based on inputs it receives, the PCM adjusts fuel
injector pulse width, idle speed, ignition spark
advance, ignition coil dwell and EVAP canister purge
operation. The PCM regulates the cooling fan, air
conditioning and speed control systems. The PCM
changes generator charge rate by adjusting the gen­erator field. The PCM also performs diagnostics.

The PCM adjusts injector pulse width (air-fuel
ratio) based on the following inputs.

• Battery voltage

• Coolant temperature

• Intake air temperature

• Exhaust gas content (oxygen sensor)

• Engine speed (crankshaft position sensor)

• Manifold absolute pressure

• Throttle position

The PCM adjusts ignition timing based on the fol­lowing inputs.

• Coolant temperature

• Intake air temperature

• Engine speed (crankshaft position sensor)

• Knock sensor

• Manifold absolute pressure

• Throttle position

14 - 26 FUEL SYSTEM PL

DESCRIPTION AND OPERATION (Continued)

• Transmission gear selection (park/neutral

switch)

The PCM also adjusts engine idle speed through
the idle air control motor based on the following
inputs.

• Air conditioning sense

• Battery voltage

• Battery temperature

• Brake switch

• Coolant temperature

• Engine speed (crankshaft position sensor)

• Engine run time

• Manifold absolute pressure

• Power steering pressure switch

• Throttle position

• Transmission gear selection (park/neutral

switch)

• Vehicle distance (speed)

The Auto Shutdown (ASD) and fuel pump relays
are mounted externally, but turned on and off by the
PCM.

The crankshaft position sensor signal is sent to the
PCM. If the PCM does not receive the signal within
approximately one second of engine cranking, it deac­tivates the ASD relay and fuel pump relay. When
these relays deactivate, power is shut off from the
fuel injectors, ignition coils, heating element in the
oxygen sensors and the fuel pump.

The PCM contains a voltage converter that
changes battery voltage to a regulated 9 volts direct
current to power the camshaft position sensor, crank­shaft position sensor and vehicle speed sensor. The
PCM also provides a 5 volt direct current supply for
the manifold absolute pressure sensor and throttle
position sensor.

AUTOMATIC SHUTDOWN (ASD) SENSE—PCM INPUT

The ASD sense circuit informs the PCM when the
ASD relay energizes. A 12 volt signal at this input
indicates to the PCM that the ASD has been acti­vated. This input is used only to sense that the ASD
relay is energized.

When energized, the ASD relay supplies battery
voltage to the fuel injectors, ignition coils and the
heating element in each oxygen sensor. If the PCM
does not receive 12 volts from this input after
grounding the ASD relay, it sets a Diagnostic Trouble
Code (DTC).

BATTERY VOLTAGE—PCM INPUT

The PCM monitors the battery voltage input to
determine fuel injector pulse width and generator
field control.

If battery voltage is low the PCM will increase
injector pulse width (period of time that the injector
is energized).

BATTERY TEMPERATURE SENSOR—PCM INPUT

The PCM uses the temperature of the battery area
to control the charge rate. The signal is used to reg­ulate the system voltage. The system voltage is
higher at cold temperatures and is gradually reduced
as temperature is increased.

BRAKE SWITCH—PCM INPUT

When the brake switch is activated, the PCM
receives an input indicating that the brakes are
being applied. The brake switch is mounted on the
brake pedal support bracket.

AIR CONDITIONING PRESSURE TRANSDUCER— PCM INPUT

The Powertrain Control Module (PCM) monitors
the A/C compressor discharge (high side) pressure
through the air conditioning pressure transducer.
The transducer supplies an input to the PCM. The
PCM engages the A/C compressor clutch if pressure
is sufficient for A/C system operation.

PL FUEL SYSTEM 14 - 27

DESCRIPTION AND OPERATION (Continued)

CAMSHAFT POSITION SENSOR—PCM INPUT

The PCM determines fuel injection synchronization
and cylinder identification from inputs provided by
the camshaft position sensor (Fig. 3) or (Fig. 4) and
crankshaft position sensor. From the two inputs, the
PCM determines crankshaft position.

CAMSHAFT POSITION SEN-SOR

Fig. 3 Camshaft Position Sensor—SOHC

Fig. 4 Camshaft Position Sensor—DOHC

The camshaft position sensor attaches to the rear
of the cylinder head. A target magnet attaches to the
rear of the camshaft and indexes to the correct posi­tion. The target magnet has four different poles
arranged in an asymmetrical pattern (Fig. 5). As the
target magnet rotates, the camshaft position sensor
senses the change in polarity (Fig. 6). The sensor out­put switch switches from high (5.0 volts) to low (0.5
volts) as the target magnet rotates. When the north
pole of the target magnet passes under the sensor,
the output switches high. The sensor output switches
low when the south pole of the target magnet passes
underneath.

The sensor also acts as a thrust plate to control
camshaft endplay.

TARGETMAGNET

Fig. 5 Target Magnet—Typical

Fig. 6 Target Magnet Polarity

CRANKSHAFT POSITION SENSOR—PCM INPUT

The PCM determines what cylinder to fire from the
crankshaft position sensor input and the camshaft
position sensor input. The second crankshaft counter­weight has two sets of four timing reference notches
including a 60 degree signature notch (Fig. 7). From
the crankshaft position sensor input the PCM deter­mines engine speed and crankshaft angle (position).

The notches generate pulses from high to low in
the crankshaft position sensor output voltage. When
a metal portion of the counterweight aligns with the
crankshaft position sensor, the sensor output voltage
goes low (less than 0.5 volts). When a notch aligns
with the sensor, voltage goes high (5.0 volts). As a
group of notches pass under the sensor, the output

MACHINED NOTCHES CRANKSHAFT POSITIONSENSOR

CRANKSHAFT POSITIONSENSOROIL FILTERGENERATOR

14 - 28 FUEL SYSTEM PL

DESCRIPTION AND OPERATION (Continued)

Fig. 7 Timing Reference Notches

voltage switches from low (metal) to high (notch)
then back to low.

If available, an oscilloscope can display the square
wave patterns of each voltage pulses. From the width
of the output voltage pulses, the PCM calculates
engine speed. The width of the pulses represent the
amount of time the output voltage stays high before
switching back to low. The period of time the sensor
output voltage stays high before switching back to
low is referred to as pulse width. The faster the
engine is operating, the smaller the pulse width on
the oscilloscope.

By counting the pulses and referencing the pulse
from the 60 degree signature notch, the PCM calcu­lates crankshaft angle (position). In each group of
timing reference notches, the first notch represents
69 degrees before top dead center (BTDC). The sec­ond notch represents 49 degrees BTDC. The third
notch represents 29 degrees. The last notch in each
set represents 9 degrees before top dead center
(TDC).

The timing reference notches are machined at 20°
increments. From the voltage pulse width the PCM
tells the difference between the timing reference
notches and the 60 degree signature notch. The 60
degree signature notch produces a longer pulse width
than the smaller timing reference notches. If the
camshaft position sensor input switches from high to
low when the 60 degree signature notch passes under
the crankshaft position sensor, the PCM knows cylin­der number one is the next cylinder at TDC.

The crankshaft position sensor mounts to the
engine block behind the alternator, just above the oil
filter (Fig. 8).

Fig. 8 Crankshaft Position Sensor

ENGINE COOLANT TEMPERATURE SENSOR—PCM INPUT

The combination coolant temperature sensor has
two elements. One element supplies coolant temper­ature signal to the PCM. The other element supplies
coolant temperature signal to the instrument panel
gauge cluster. The PCM determines engine coolant
temperature from the coolant temperature sensor.

As coolant temperature varies the coolant temper­ature sensors resistance changes resulting in a differ­ent input voltage to the PCM and the instrument
panel gauge cluster.

When the engine is cold, the PCM will provide
slightly richer air- fuel mixtures and higher idle
speeds until normal operating temperatures are
reached.

ENGINE COOLANTTEMPERATURESENSORCAMSHAFTPOSITIONSENSOR

FUEL RAIL

COOLANT TEMPER-ATURE SENSOR

PL FUEL SYSTEM 14 - 29

DESCRIPTION AND OPERATION (Continued)

SOHC

The coolant sensor threads into the rear of the cyl-

inder head, next to the camshaft position sensor (Fig.

9). New sensors have sealant applied to the threads.

Fig. 9 Engine Coolant Temperature Sensor—SOHC

DOHC

The coolant sensor threads into the intake mani­fold next to the thermostat housing (Fig. 10). New
sensors have sealant applied to the threads.

Fig. 10 Engine Coolant Temperature Sensor—DOHC

FUEL LEVEL SENSOR—PCM INPUT

The fuel level sensor (fuel gauge sending unit)
sends a signal to the PCM to indicate fuel level. The
purpose of this feature is to prevent a false setting of
misfire and fuel system monitor trouble codes if the
fuel level is less than approximately 15 percent of its
rated capacity. It is also used to send a signal for fuel
gauge operation via the CCD bus circuits.

HEATED OXYGEN SENSOR (O2S SENSOR)—PCM INPUT

As vehicles accumulate mileage, the catalytic con­vertor deteriorates. The deterioration results in a

less efficient catalyst. To monitor catalytic convertor
deterioration, the fuel injection system uses two
heated oxygen sensors. One sensor upstream of the
catalytic convertor, one downstream of the convertor.
The PCM compares the reading from the sensors to
calculate the catalytic convertor oxygen storage
capacity and converter efficiency. Also, the PCM uses
the upstream heated oxygen sensor input when
adjusting injector pulse width.

When the catalytic converter efficiency drops below
emission standards, the PCM stores a diagnostic
trouble code and illuminates the malfunction indica­tor lamp (MIL).

The O2S sensors produce voltages from 0 to 1 volt,
depending upon the oxygen content of the exhaust
gas in the exhaust manifold. When a large amount of
oxygen is present (caused by a lean air/fuel mixture),
the sensors produces a low voltage. When there is a
lesser amount present (rich air/fuel mixture) it pro­duces a higher voltage. By monitoring the oxygen
content and converting it to electrical voltage, the
sensors act as a rich- lean switch.

The oxygen sensors are equipped with a heating
element that keeps the sensors at proper operating
temperature during all operating modes. Maintaining
correct sensor temperature at all times allows the
system to enter into closed loop operation sooner.
Also, it allows the system to remain in closed loop
operation during periods of extended idle.

In Closed Loop operation the PCM monitors the
O2S sensor input (along with other inputs) and
adjusts the injector pulse width accordingly. During
Open Loop operation the PCM ignores the O2 sensor
input. The PCM adjusts injector pulse width based
on preprogrammed (fixed) values and inputs from
other sensors.

The Automatic Shutdown (ASD) relay supplies bat­tery voltage to both the upstream and downstream
heated oxygen sensors. The oxygen sensors are
equipped with a heating element. The heating ele­ments reduce the time required for the sensors to
reach operating temperature.

UPSTREAM OXYGEN SENSOR

The input from the upstream heated oxygen sensor
tells the PCM the oxygen content of the exhaust gas.
Based on this input, the PCM fine tunes the air-fuel
ratio by adjusting injector pulse width.

The sensor input switches from 0 to 1 volt, depending
upon the oxygen content of the exhaust gas in the
exhaust manifold. When a large amount of oxygen is
present (caused by a lean air-fuel mixture), the sensor
produces voltage as low as 0.1 volt. When there is a
lesser amount of oxygen present (rich air-fuel mixture)
the sensor produces a voltage as high as 1.0 volt. By
monitoring the oxygen content and converting it to elec­trical voltage, the sensor acts as a rich-lean switch.

OXYGEN SEN-SORSEXHAUSTMANIFOLD

CATALYTIC CON-VERTORDOWNSTREAM OXYGENSENSOR

14 - 30 FUEL SYSTEM PL

DESCRIPTION AND OPERATION (Continued)

The heating element in the sensor provides heat to
the sensor ceramic element. Heating the sensor
allows the system to enter into closed loop operation
sooner. Also, it allows the system to remain in closed
loop operation during periods of extended idle.

In Closed Loop, the PCM adjusts injector pulse
width based on the upstream heated oxygen sensor
input along with other inputs. In Open Loop, the
PCM adjusts injector pulse width based on prepro­grammed (fixed) values and inputs from other sen­sors.

The upstream oxygen sensor threads into the out­let flange of the exhaust manifold (Fig. 11).

Fig. 12 Downstream Heated Oxygen Sensor

The IAT sensor and Manifold Absolute Pressure
(MAP) switch are a combined into a single sensor
that attachs to the intake manifold (Fig. 13) or (Fig.

14).

Fig. 11 Upstream Heated Oxygen Sensor

DOWNSTREAM OXYGEN SENSOR

The downstream heated oxygen sensor threads into
the outlet pipe at the rear of the catalytic convertor
(Fig. 12). The downstream heated oxygen sensor
input is used to detect catalytic convertor deteriora­tion. As the convertor deteriorates, the input from
the downstream sensor begins to match the upstream
sensor input except for a slight time delay. By com­paring the downstream heated oxygen sensor input
to the input from the upstream sensor, the PCM cal­culates catalytic convertor efficiency.

IGNITION CIRCUIT SENSE—PCM INPUT

The ignition circuit sense input tells the Power­train Control Module (PCM) the ignition switch has
energized the ignition circuit. Refer to the wiring dia­grams for circuit information.

INTAKE AIR TEMPERATURE SENSOR—PCM INPUT

The Intake Air Temperature (IAT) sensor measures
the temperature of the intake air as it enters the
engine. The sensor supplies one of the inputs the
PCM uses to determine injector pulse width and
spark advance.

As Intake Air temperature varies the Intake Air
Temperature sensors resistance changes resulting in
a different input voltage to the PCM.

INTAKE MANI-FOLD MAP/AIR TEM-PERATURESENSOR

FUEL RAIL

Fig. 13 / MAP/Intake Air Temperature Sensor—SOHC

Fig. 14 MAP/Intake Air Temperature Sensor—DOHC

KNOCK SEN-SORSTARTERMOTOR

PL FUEL SYSTEM 14 - 31

DESCRIPTION AND OPERATION (Continued)

KNOCK SENSOR—PCM INPUT

The knock sensor threads into the side of the cyl­inder block in front of the starter (Fig. 15). When the
knock sensor detects a knock in one of the cylinders,
it sends an input signal to the PCM. In response, the
PCM retards ignition timing for all cylinders by a
scheduled amount.

Knock sensors contain a piezoelectric material
which sends an input voltage (signal) to the PCM. As
the intensity of the engine knock vibration increases,
the knock sensor output voltage also increases.

POWER STEERING PRESSURE SWITCH—PCM
INPUT

A pressure sensing switch is located on the power
steering gear. The switch (Fig. 16) provides an input
to the PCM during periods of high pump load and
low engine RPM; such as during parking maneuvers.

When power steering pump pressure exceeds 2758
kPa (400 psi), the switch is open. The PCM increases
idle air flow through the IAC motor to prevent
engine stalling. When pump pressure is low, the
switch is closed.

POWER STEERINGPRESSURE SWITCH

Fig. 15 Knock Sensor

MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSOR—PCM INPUT

The PCM supplies 5 volts direct current to the
MAP sensor. The MAP sensor converts intake mani­fold pressure into voltage. The PCM monitors the
MAP sensor output voltage. As vacuum increases,
MAP sensor voltage decreases proportionately. Also,
as vacuum decreases, MAP sensor voltage increases
proportionately.

At key on, before the engine is started, the PCM
determines atmospheric air pressure from the MAP
sensor voltage. While the engine operates, the PCM
determines intake manifold pressure from the MAP
sensor voltage. Based on MAP sensor voltage and
inputs from other sensors, the PCM adjusts spark
advance and the air/fuel mixture.

The MAP/Intake Air Temperature sensor mounts to
the intake manifold (Fig. 13) and (Fig. 14).

Fig. 16 Power Steering Pressure Switch

SENSOR RETURN—PCM INPUT

The sensor return circuit provides a low electrical
noise ground reference for all of the systems sensors.
The sensor return circuit connects to internal ground
circuits within the powertrain control module.

SPEED CONTROL—PCM INPUT

The speed control system provides five separate
voltages (inputs) to the Powertrain Control Module
(PCM). The voltages correspond to the ON/OFF, SET,
RESUME and CANCEL.

The speed control ON voltage informs the PCM
that the speed control system has been activated.
The speed control SET voltage informs the PCM that
a fixed vehicle speed has been selected. The speed
control RESUME voltage indicates the previous fixed
speed is requested. The speed control CANCEL volt­age tells the PCM to deactivate but retain set speed
in memory (same as depressing the brake pedal). The
speed control OFF voltage tells the PCM that the
speed control system has deactivated. Refer to Group
8H for more speed control information.

PARK/NEUTRALSWITCHTRANSAXLEHOUSING

14 - 32 FUEL SYSTEM PL

DESCRIPTION AND OPERATION (Continued)

THROTTLE SHIELDPURGE HOSETHROTTLE POSITION SEN-SORIDLE CONTROL MOTOR

IDLE AIR CONTROLMOTOR THROTTLEPOSITION SEN-SOR

SCI RECEIVE—PCM INPUT

SCI Receive is the serial data communication
receive circuit for the DRB scan tool. The Powertrain
Control Module (PCM) receives data from the DRB
through the SCI Receive circuit.

Along with inputs from other sensors, the PCM
uses the TPS input to determine current engine oper­ating conditions. The PCM also adjusts fuel injector
pulse width and ignition timing based on these
inputs.

PARK/NEUTRAL POSITION SWITCH—PCM INPUT

The park/neutral position switch is located on the
automatic transaxle housing (Fig. 17). Manual tran­saxles do not use park/neutral switches. The switch
provides an input to the PCM to indicate whether
the automatic transaxle is in Park/Neutral, or a drive
gear selection. This input is used to determine idle
speed (varying with gear selection) and ignition tim­ing advance. The park/neutral input is also used to
cancel vehicle speed control. The park/neutral switch
is sometimes referred to as the neutral safety switch.

Fig. 17 Park/Neutral Switch

THROTTLE POSITION SENSOR—PCM INPUT

The throttle position sensor mounts to the side of
the throttle body (Fig. 18) and (Fig. 19).

The Throttle Position Sensor (TPS) connects to the
throttle blade shaft. The TPS is a variable resistor
that provides the PCM with an input signal (voltage).
The signal represents throttle blade position. As the
position of the throttle blade changes, the resistance
of the TPS changes.

The PCM supplies approximately 5 volts DC to the
TPS. The TPS output voltage (input signal to the
powertrain control module) represents throttle blade
position. The TPS output voltage to the PCM varies
from approximately 0.35 to 1.03 volts at minimum
throttle opening (idle) to a maximum of 3.1 to 4.0
volts at wide open throttle.

Fig. 18 Throttle Position Sensor and Idle Air Control

Motor—SOHC

Fig. 19 Throttle Position Sensor and Idle Air Control

Motor—DOHC

VEHICLESPEEDSENSOR

TRANSAXLE
EXTENSION

HOUSING

TRANSAXLE SPEEDSENSORSPEED SENSOR RETAININGBOLT

PL FUEL SYSTEM 14 - 33

DESCRIPTION AND OPERATION (Continued)

VEHICLE SPEED SENSOR—PCM INPUT

The vehicle speed sensor is located in the transmis­sion extension housing (Fig. 20) and (Fig. 21). The
sensor input is used by the PCM to determine vehicle
speed and distance traveled.

The vehicle speed sensor generates 8 pulses per sen­sor revolution. These signals, in conjunction with a
closed throttle signal from the throttle position sensor,
indicate a closed throttle deceleration to the PCM.
Under deceleration conditions, the PCM adjusts the Idle
Air Control (IAC) motor to maintain a desired MAP
value.

When the vehicle is stopped at idle, a closed throt­tle signal is received by the PCM (but a speed sensor
signal is not received). Under idle conditions, the
PCM adjusts the IAC motor to maintain a desired
engine speed.

The vehicle speed sensor signal is also used to
operate the following functions or systems:

• Speedometer

• Speed control

Daytime Running Lights (Canadian Vehicles only).

•

PDC. The inside top of the PDC cover has a label
showing relay and fuse location.

Fig. 21 Vehicle Speed Sensor—Manual

Transmission

The air conditioning clutch relay is located in the

AUTOMATIC SHUTDOWN RELAY—PCM OUTPUT

The automatic shutdown (ASD) relay supplies bat­tery voltage to the fuel injectors, electronic ignition
coil and the heating elements in the oxygen sensors.

A buss bar in the power distribution center (PDC)
supplies voltage to the solenoid side and contact side
of the relay. The ASD relay power circuit contains a
20 amp fuse between the buss bar in the PDC and
the relay. The fuse also protects the power circuit for
the fuel pump relay and pump. The fuse is located in
the PDC. Refer to Group 8W, Wiring Diagrams for
circuit information.

The PCM controls the relay by switching the
ground path for the solenoid side of the relay on and
off. The PCM turns the ground path off when the
ignition switch is in the Off position unless the 02

Fig. 20 Vehicle Speed Sensor—Automatic

Transmission

AIR CONDITIONING CLUTCH RELAY—PCM OUTPUT

The PCM controls the air conditioning clutch relay
ground circuit. Buss bars in the Power Distribution
Center (PDC) supply voltage to the solenoid side and
power side of the relay. When the PCM receives an
air conditioning input, it grounds the A/C compressor
clutch relay and the radiator fan relay.

When the PCM senses low idle speeds or wide open
throttle through the throttle position sensor, it removes
the ground for the A/C compressor clutch relay. When
the relay de-energizes, the contacts open preventing air
conditioning clutch engagement. Also, if the PCM senses
a part throttle launch condition, it disables the A/C com­pressor clutch for several seconds.

Heater Monitor test is being run. Refer to Group 25,
On-Board Diagnostics. When the ignition switch is in
the On or Crank position, the PCM monitors the
crankshaft position sensor and camshaft position sen­sor signals to determine engine speed and ignition
timing (coil dwell). If the PCM does not receive the
crankshaft position sensor and camshaft position sen­sor signals when the ignition switch is in the Run
position, it will de- energize the ASD relay.

The ASD relay is located in the PDC. The inside
top of the PDC cover has a label showing relay and
fuse location.

CHARGING SYSTEM INDICATOR LAMP—PCM OUTPUT

The PCM turns the instrument panel Charging
System Lamp on. Refer to Group 8C for charging sys­tem information.

DUTY CYCLE EVAPPURGE SOLENOIDVALVE ENGINEMOUNT

14 - 34 FUEL SYSTEM PL

DESCRIPTION AND OPERATION (Continued)

FUEL PUMP RELAY—PCM OUTPUT

The fuel pump relay supplies battery voltage to the
fuel pump. A buss bar in the Power Distribution Cen­ter (PDC) supplies voltage to the solenoid side and
contact side of the relay. The fuel pump relay power
circuit contains a 20 amp fuse between the buss bar
in the PDC and the relay. The fuse also protects the
power circuit for the Automatic Shutdown (ASD)
relay. The fuse is located in the PDC. Refer to Group
8W, Wiring Diagrams for circuit information.

The PCM controls the fuel pump relay by switch­ing the ground path for the solenoid side of the relay
on and off. The PCM turns the ground path off when
the ignition switch is in the Off position. When the
ignition switch is in the On position, the PCM ener­gizes the fuel pump. If the crankshaft position sensor
does not detect engine rotation, the PCM de- ener­gizes the relay after approximately one second.

The fuel pump relay is located in the PDC. The
inside top of the PDC cover has a label showing relay
and fuse location.

DUTY CYCLE EVAP PURGE SOLENOID—PCM OUTPUT

The duty cycle EVAP purge solenoid regulates the
rate of vapor flow from the EVAP canister to the
throttle body. The powertrain control module oper­ates the solenoid.

During the cold start warm-up period and the hot
start time delay, the PCM does not energize the sole­noid. When de-energized, no vapors are purged.

The engine enters closed loop operation after it
reaches a specified temperature and the programmed
time delay ends. During closed loop operation, the
PCM energizes and de-energizes the solenoid 5 to 10
times per second, depending upon operating condi­tions. The PCM varies the vapor flow rate by chang­ing solenoid pulse width. Pulse width is the amount
of time the solenoid is energized.

The solenoid attaches to a bracket near the front
engine mount (Fig. 22). To operate correctly, the sole­noid must be installed with the electrical connector
on top.

ELECTRIC EGR TRANSDUCER—PCM OUTPUT

The Electric EGR Transducer contains an electri­cally operated solenoid and a back-pressure con­trolled vacuum transducer (Fig. 23). The PCM
operates the solenoid based on inputs from the multi­port fuel injection system. The transducer and EGR
valve are serviced as an assembly.

When the PCM energizes the solenoid, vacuum
does not reach the transducer. Vacuum flows to the
transducer when the PCM de-energizes the solenoid.

When exhaust system back-pressure becomes high
enough, it fully closes a bleed valve in the vacuum

Fig. 22 Duty Cycle EVAP Purge Solenoid

transducer. When the PCM de-energizes the solenoid
and back-pressure closes the transducer bleed valve,
vacuum flows through the transducer to operate the
EGR valve.

De-energizing the solenoid, but not fully closing the
transducer bleed hole (because of low back-pressure),
varies the strength of the vacuum signal applied to
the EGR valve. Varying the strength of the vacuum
signal changes the amount of EGR supplied to the
engine. This provides the correct amount of exhaust
gas recirculation for different operating conditions.

The transducer and EGR valve mount to the rear
of the cylinder head (Fig. 23).

GENERATOR FIELD—PCM OUTPUT

The PCM regulates the charging system voltage
within a range of 12.9 to 15.0 volts. Refer to Group
8A for Battery system information and 8C for charg­ing system information.

IDLE AIR CONTROL MOTOR—PCM OUTPUT

The Idle Air Control (IAC) motor is mounted on the
throttle body. The PCM operates the idle air control
motor (Fig. 24). The PCM adjusts engine idle speed
through the idle air control motor to compensate for
engine load, coolant temperature or barometric pres­sure changes.

The throttle body has an air bypass passage that
provides air for the engine during closed throttle idle.
The idle air control motor pintle protrudes into the
air bypass passage and regulates air flow through it.

The PCM adjusts engine idle speed by moving the
IAC motor pintle in and out of the bypass passage.

EGR TRANSDUCEREGR VALVESERVICE PORTCAM SENSOR

IDLE AIRCONTROLMOTOR FRESH AIROPENING

DATA LINK CONNECTOR

PL FUEL SYSTEM 14 - 35

DESCRIPTION AND OPERATION (Continued)

Fig. 25 Data Link Connector

FUEL INJECTORS—PCM OUTPUT

Fig. 23 Electric EGR Backpressure Transducer—

Typical

The adjustments are based on inputs the PCM
receives. The inputs are from the throttle position
sensor, crankshaft position sensor, coolant tempera­ture sensor, MAP sensor, vehicle speed sensor and
various switch operations (brake, park/neutral, air
conditioning).

The 2.0L engine uses electrically operated top feed
fuel injectors (Fig. 26). The Automatic Shutdown
(ASD) relay supplies battery voltage to the fuel injec­tors. The PCM controls the ground path for each
injector in sequence. By switching the ground paths
on and off, the PCM fine-tunes injector pulse width.
Injector pulse width refers to the amount of time an
injector operates.

The PCM determines injector synchronization from
the camshaft position sensor and crankshaft position
sensor inputs. The PCM grounds the ASD and fuel
pump relays after receiving the camshaft position
sensor and crankshaft position sensor inputs.

The PCM energizes the injectors in a sequential
order during all engine operating conditions except

FUEL INJECTORTOP (FUEL ENTRY) NOZZLE

start-up. For the first injector pulse width during
start-up, all injectors are energized at the same time.
Once the PCM determines crankshaft position, it
begins energizing the injectors in sequence.

Fig. 24 Idle Air Control Motor Air Bypass Passage—

Typical

DATA LINK CONNECTOR

The data link connector (diagnostic connector)
links the DRB scan tool with the powertrain control
module (PCM). Refer to On-Board Diagnostics in the
General Diagnosis section of this group. The data
link connector is located inside the vehicle, under the
instrument panel, left of the steering column (Fig.

25).

Fig. 26 Fuel Injector

14 - 36 FUEL SYSTEM PL

DESCRIPTION AND OPERATION (Continued)

IGNITION COIL—PCM OUTPUT

The coil assembly consists of 2 coils molded
together. The coil assembly is mounted over the valve
cover (Fig. 27) or (Fig. 28). High tension leads route
to each cylinder from the coil. The coil fires two
spark plugs every power stroke. One plug is the cyl­inder under compression, the other cylinder fires on
the exhaust stroke. Coil number one fires cylinders 1
and 4. Coil number two fires cylinders 2 and 3. The
PCM determines which of the coils to charge and fire
at the correct time.

The Auto Shutdown (ASD) relay provides battery
voltage to the ignition coil. The PCM provides a
ground contact (circuit) for energizing the coil. When
the PCM breaks the contact, the energy in the coil
primary transfers to the secondary causing the
spark. The PCM will de-energize the ASD relay if it
does not receive the crankshaft position sensor and
camshaft position sensor inputs. Refer to Auto Shut­down (ASD) Relay—PCM Output in this section for
relay operation.

MALFUNCTION INDICATOR (CHECK ENGINE)
LAMP—PCM OUTPUT

The PCM supplies the malfunction indicator (check
engine) lamp on/off signal to the instrument panel
through the CCD Bus. The CCD Bus is a communi­cations port. Various modules use the CCD Bus to
exchange information.

The Check Engine lamp comes on each time the
ignition key is turned ON and stays on for 3 seconds
as a bulb test.

The Malfunction Indicator Lamp (MIL) stays on
continuously, when the PCM has entered a Limp-In
mode or identified a failed emission component. Dur­ing Limp-in Mode, the PCM attempts to keep the
system operational. The MIL signals the need for
immediate service. In limp-in mode, the PCM com­pensates for the failure of certain components that
send incorrect signals. The PCM substitutes for the
incorrect signals with inputs from other sensors.

If the PCM detects active engine misfire severe
enough to cause catalyst damage, it flashes the MIL.
At the same time the PCM also sets a Diagnostic
Trouble Code (DTC).

For signals that can trigger the MIL (Check
Engine Lamp) refer to Group 25, On-Board
Dianostics.

The MIL can also display diagnostic trouble codes.
Cycle the ignition switch on, off, on, off, on, within 5
seconds and any diagnostic trouble codes stored in
the PCM will be displayed. Refer to On-Board Diag­nostics in Group 25, Emission Control Systems Diag­nostic Trouble Code Descriptions.

IGNITIONCOILSSPARK PLUGINSULATOR

Fig. 27 Ignition Coil Pack—SOHC

Fig. 28 Ignition Coil Pack—DOHC

RADIATOR FAN CONTROL MODULE—PCM OUTPUT

The radiator fan runs when coolant temperature
and A/C system pressure demand cooling. The radia­tor fan circuit contains a Pulse Width Module
(PWM). Refer to the Group 8W for a circuit sche­matic.

A 5 volt signal is supplied to the PWM. The PCM
provides a pulsed ground for the PWM. Depending
upon the amount of pulse on time, the PWM puts out
a proportional voltage to the fan motor at the lower
speed. For instance, if the on time is 30 percent, then
the voltage to the fan motor will be 3.6 volts.

When engine coolant reaches approximately 99°C
(210°F) the PCM grounds the PWM relay. When the
PCM grounds the relay it operates at a 30% duty
cycle and immediately ramps up to 100% duty cycle.
The PCM de-energizes the PWM relay when coolant
temperature drops to approximately 93°C (199°F).

Also, when the air conditioning pressure switch
closes, the PCM grounds the PWM. The air condi­tioning switch closes at 285 psi 610 psi. When air

TORQUE CON-VERTORCLUTCH SOLE-NOIDAUTOMATICTRANSAXLEHOUSING PARK/NEUTRAL SWITCH

POWER DIS-TRIBUTIONCENTER SPEED CONTROLSERVOWINDSHIELDWASHER FLUIDBOTTLEPCMBATTERY

PL FUEL SYSTEM 14 - 37

DESCRIPTION AND OPERATION (Continued)

conditioning pressure drops approximately 40 psi, the
pressure switch opens and the fan turns off.

The PWM relay is located on the left front inner

frame just behind the radiator.

SPEED CONTROL—PCM INPUT

The speed control system provides five separate
voltages (inputs) to the Powertrain Control Module
(PCM). The voltages correspond to the ON/OFF, SET,
RESUME and CANCEL.

The speed control ON voltage informs the PCM
that the speed control system has been activated.
The speed control SET voltage informs the PCM that
a fixed vehicle speed has been selected. The speed
control RESUME voltage indicates the previous fixed
speed is requested. The speed control CANCEL volt­age tells the PCM to deactivate but retain set speed
in memory (same as depressing the brake pedal). The
speed control OFF voltage tells the PCM that the
speed control system has deactivated. Refer to Group
8H for more speed control information.

Fig. 29 Torque Convertor Clutch Solenoid

SCI RECEIVE—PCM INPUT

SCI Receive is the serial data communication
receive circuit for the DRB scan tool. The Powertrain
Control Module (PCM) receives data from the DRB
through the SCI Receive circuit.

TACHOMETER—PCM OUTPUT

The PCM operates the tachometer on the instru­ment panel. The PCM calculates engine RPM from
the crankshaft position sensor input.

TORQUE CONVERTOR CLUTCH SOLENOID—PCM OUTPUT

Three-speed automatic transaxles use a torque con­verter clutch solenoid. The PCM controls the engage­ment of the torque converter clutch through the
solenoid (Fig. 29). The torque converter clutch is
engaged up only in direct drive mode. Refer to Group
21 for transmission information.

DIAGNOSIS AND TESTING

VISUAL INSPECTION—SOHC

Before diagnosing or servicing the fuel injection
system, perform a visual inspection for loose, discon­nected, or misrouted wires and hoses (Fig. 30). A
thorough visual inspection that includes the following
checks saves unnecessary test and diagnostic time.

(1) Inspect the battery connections. Clean corroded
terminals (Fig. 31).

(2) Check the 2 PCM 40-way connector for
stretched wires on pushed out terminals (Fig. 31).

Fig. 30 2.0L SOHC Engine Compartment

Fig. 31 Battery, PCM, and PDC

POWER DISTRI-BUTION CEN-TER FUSESRELAYS

SPEED CON-TROL CABLE THROTTLECABLETRANSMISSIONKICKDOWNCABLE

14 - 38 FUEL SYSTEM PL

IDLE AIR CONTROL MOTORTPS

DIAGNOSIS AND TESTING (Continued)

(3) Open the Power Distribution Center (PDC).
Check for blown fuses. Ensure the relays and fuses
are fully seated in the PDC (Fig. 32). A label on the
underside of the PDC cover shows the locations of
each relay and fuse.

(5) Check the electrical connections at the idle air

CONNECTION TO VALVECOVERPCV VALVECONNECTION TO INTAKEMANIFOLD

control motor and throttle position sensor (Fig. 34).

Fig. 32 Power Distribution Center

(4) Verify the throttle cable operates freely (Fig.

33).

Fig. 33 Throttle Cable—Automatic Transmission

Fig. 34 Idle Air Control Motor and Throttle Position

Sensor—Typical

(6) Check hose connections between the PCV
valve, vacuum port - intake manifold and the oil sep­arator (Fig. 35).

Fig. 35 PCV Valve

MAP/AIR TEMPERATURESENSORPCV VACUUM NIPPLEINTAKE MANIFOLD

FUEL SUP-

PLY LINE

FUEL LINEQUICK-CONNECTSIGNITION COILFUELRAIL

FUEL INJEC-

TOR

PL FUEL SYSTEM 14 - 39

DIAGNOSIS AND TESTING (Continued)

IGNITIONCOILSSPARK PLUG CABLESPARK PLUGINSULATOR

(7) Inspect the electrical connections at the MAP

sensor/intake air temperature sensor and the (Fig.

36).

Fig. 36 MAPIntake Air Temperature Sensor

(8) Inspect the fuel injector electrical connections

(Fig. 37).

(9) Inspect the ignition coil electrical connector.

DUTY CYCLE EVAPPURGE SOLENOIDVALVE ENGINEMOUNT

Ensure the spark plug insulators are firmly seated
over the spark plugs (Fig. 38).

Fig. 38 Ignition Coil and Spark Plugs—Typical

(10) Inspect the electrical and hose connections at
the duty cycle purge solenoid (Fig. 39).

Fig. 37 Fuel Injectors

Fig. 39 Duty Cycle Purge Solenoid

14 - 40 FUEL SYSTEM PL

DIAGNOSIS AND TESTING (Continued)

(11) Check the electrical connection to the radiator

STARTER

MOTOR

fan.

STARTER SOLENOIDGROUNDSTRAP

(12) Inspect for corrosion on the electrical connec­tions at the starter motor solenoid. Check the ground
cable connection below the starter motor (Fig. 40).

Fig. 40 Starter Motor and Ground Strap

(13) Inspect the air cleaner filter element. Replace

KNOCK SEN-SORSTARTERMOTOR

as necessary. Check the air induction system for
restrictions.

(14) Check the electrical connection at the knock
sensor (Fig. 41).

Fig. 42 Camshaft Position Sensor and Engine

Coolant Temperature Sensor

Fig. 41 Knock Sensor

(15) Check the electrical connections at the cam­shaft position sensor and engine coolant temperature
sensor (Fig. 42).

(16) Check the electrical connector at the Elec­tronic EGR Transducer. Inspect the vacuum and back
pressure hoses at the solenoid and transducer for
leaks (Fig. 43).

(17) Inspect the electrical connections at the gen­erator (Fig. 44). Check the generator belt for glazing
or damage.

GENERATOR

Fig. 43 Electronic EGR Transducer

Fig. 44 Generator

CRANKSHAFT POSITIONSENSOROIL FILTERGENERATOR

VEHICLESPEEDSENSOR

POWER STEERINGPRESSURE SWITCH

TRANSAXLE
EXTENSION

HOUSING

TORQUE CON-VERTORCLUTCH SOLE-NOIDAUTOMATICTRANSAXLEHOUSING PARK/NEUTRAL SWITCH

OXYGEN SEN-SORSEXHAUSTMANIFOLD

PL FUEL SYSTEM 14 - 41

DIAGNOSIS AND TESTING (Continued)

(18) Inspect the electrical connector at the crank­shaft position sensor (Fig. 45).

Fig. 45 Crankshaft Position Sensor

(19) Check the electrical connection at the vehicle
speed sensor (Fig. 46).

(21) On vehicles with automatic transaxles, check
the electrical connections at the park/neutral switch
and the torque convertor clutch solenoid (Fig. 48).

Fig. 48 Park/Neutral Switch and Torque Convertor

Clutch Solenoid

(22) Inspect the electrical connections at the
upstream and downstream heated oxygen sensors
(Fig. 49) and (Fig. 50).

Fig. 46 Vehicle Speed Sensor

(20) Check the electrical connection at the power
steering pressure switch on the power steering gear
housing (Fig. 47).

Fig. 47 Power Steering Pressure Switch

CATALYTIC CON-VERTORDOWNSTREAM OXYGENSENSOR

Fig. 49 Upstream Heated Oxygen Sensor

Fig. 50 Downstream Heated Oxygen Sensor

ELECTRICAL CON-

NECTOR

BATTERY TRAYBATTERY TEMPERATURESENSORAIR INLETTUBE

FUEL LINE

POWER DIS-TRIBUTIONCENTER SPEED CONTROLSERVOWINDSHIELDWASHER FLUIDBOTTLEPCMBATTERY

14 - 42 FUEL SYSTEM PL

DIAGNOSIS AND TESTING (Continued)

(23)

Inspect the fuel pump module electrical connec­tion at the fuel tank for corrosion or damage (Fig. 51).
Check for pinched, kinked or damaged fuel supply tube.

Fig. 53 2.0L DOHC Engine Compartment

(2) Check the 2 PCM 40-way connector for

stretched wires on pushed out terminals (Fig. 54).

Fig. 51 Fuel Pump Module Electrical Connector

(24) Inspect the connections to the speed control
servo, if equipped (Fig. 31). Refer to Group 8H, Vehi­cle Speed Control.

Fig. 52 Battery Temp. Sensor Connectors

(25) Inspect the connection at the battery temper­ature sensor (Fig. 52).

VISUAL INSPECTION—DOHC

Before diagnosing or servicing the fuel injection
system, perform a visual inspection for loose, discon­nected, or misrouted wires and hoses (Fig. 53). A
thorough visual inspection that includes the following
checks saves unnecessary test and diagnostic time.

(1) Inspect the battery connections. Clean corroded
terminals (Fig. 31).

Fig. 54 Battery, PCM, and PDC

POWER DISTRI-BUTION CEN-TER FUSESRELAYS

(3)

Open the Power Distribution Center (PDC). Check
for blown fuses. Ensure the relays and fuses are fully
seated in the PDC (Fig. 55). A label on the underside of
the PDC cover shows the locations of each relay and fuse.

Fig. 55 Power Distribution Center

SPEED CON-TROL CABLE THROTTLECABLETRANSMISSIONKICKDOWNCABLE

IDLE AIR CONTROLMOTOR THROTTLEPOSITION SEN-SOR

INTAKE MANI-FOLD MAP/AIR TEM-PERATURESENSOR

FUEL SUP-

PLY LINE

PCV VALVE #1 SPARK PLUGBOOT

FUEL RAIL

FUEL LINEQUICK-CONNECTSIGNITION COILFUELRAIL

FUEL INJEC-

TOR

PL FUEL SYSTEM 14 - 43

DIAGNOSIS AND TESTING (Continued)

(4) Verify the throttle cable operates freely (Fig.

56).

Fig. 58 PCV Valve

Fig. 56 Throttle Cable—Automatic Transmission

(5) Check the electrical connections at the idle air

control motor and throttle position sensor (Fig. 57).

Fig. 57 Idle Air Control Motor and Throttle Position

Sensor—Typical

(6) Check hose connections between the PCV
valve, vacuum port - intake manifold and the oil sep­arator (Fig. 58).

(7) Inspect the electrical connections at the MAP
sensor/intake air temperature sensor and the (Fig.

59).

(8) Inspect the fuel injector electrical connections
(Fig. 60).

Fig. 59 MAP/Intake Air Temperature Sensor

Fig. 60 Fuel Injectors—Typical

KNOCK SEN-SORSTARTERMOTOR

DUTY CYCLE EVAPPURGE SOLENOIDVALVE ENGINEMOUNT

IGNITION COIL FAS-

TENERS

ELECTRICALCONNECTOR

STARTER

MOTOR

STARTER SOLENOIDGROUNDSTRAP

14 - 44 FUEL SYSTEM PL

DIAGNOSIS AND TESTING (Continued)

(9) Inspect the ignition coil electrical connector.
Ensure the spark plug insulators are firmly seated
over the spark plugs (Fig. 61).

Fig. 61 Ignition Coil and Spark Plugs

(10) Inspect the electrical and hose connections at
the duty cycle purge solenoid (Fig. 62).

Fig. 63 Starter Motor and Ground Strap

(14) Check the electrical connection at the knock

sensor (Fig. 64).

CAMSHAFT POSITION SEN-SOR

Fig. 64 Knock Sensor

(15) Check the electrical connections at the cam­shaft position sensor (Fig. 65) and engine coolant
temperature sensor (Fig. 66).

Fig. 62 Duty Cycle Purge Solenoid

(11) Check the electrical connection to the radiator

fan.

(12) Inspect for corrosion on the electrical connec­tions at the starter motor solenoid. Check the ground
cable connection below the starter motor (Fig. 63).

(13) Inspect the air cleaner filter element. Replace
as necessary. Check the air induction system for
restrictions.

Fig. 65 Camshaft Position Sensor

EGR TRANSDUCEREGR VALVESERVICE PORTCAM SENSOR

FUEL RAIL

COOLANT TEMPER-ATURE SENSOR

CRANKSHAFT POSITIONSENSOROIL FILTERGENERATOR

VEHICLESPEEDSENSOR

GENERATOR

TRANSAXLE
EXTENSION

HOUSING

PL FUEL SYSTEM 14 - 45

DIAGNOSIS AND TESTING (Continued)

Fig. 66 Engine Coolant Temperature Sensor

(16) Check the electrical connector at the Elec­tronic EGR Transducer. Inspect the vacuum and back
pressure hoses at the solenoid and transducer for
leaks (Fig. 67).

Fig. 68 Generator

Fig. 69 Crankshaft Position Sensor

Fig. 67 Electronic EGR Transducer

(17) Inspect the electrical connections at the gen­erator (Fig. 68). Check the generator belt for glazing
or damage.

(18) Inspect the electrical connector at the crank­shaft position sensor (Fig. 69).

(19) Check the electrical connection at the vehicle
speed sensor (Fig. 70).

Fig. 70 Vehicle Speed Sensor

TORQUE CON-VERTORCLUTCH SOLE-NOIDAUTOMATICTRANSAXLEHOUSING PARK/NEUTRAL SWITCH

POWER STEERINGPRESSURE SWITCH

CATALYTIC CON-VERTORDOWNSTREAM OXYGENSENSOR

ELECTRICAL CON-

NECTOR

OXYGEN SEN-SORSEXHAUSTMANIFOLD

FUEL LINE

14 - 46 FUEL SYSTEM PL

DIAGNOSIS AND TESTING (Continued)

(20) Check the electrical connection at the power
steering pressure switch on the power steering gear
housing (Fig. 71).

Fig. 73 Upstream Heated Oxygen Sensor

Fig. 71 Power Steering Pressure Switch

(21) On vehicles with automatic transaxles, check
the electrical connections at the park/neutral switch
and the torque convertor clutch solenoid (Fig. 72).

Fig. 72 Park/Neutral Switch and Torque Convertor

Clutch Solenoid

(22) Inspect the electrical connections at the
upstream and downstream heated oxygen sensors
(Fig. 73) and (Fig. 74).

(23) Inspect the fuel pump module electrical con­nection at the fuel tank for corrosion or damage (Fig.

75). Check for pinched, kinked or damaged fuel sup­ply tube.

Fig. 74 Downstream Heated Oxygen Sensor

Fig. 75 Fuel Pump Module Electrical Connector

BATTERY TRAYBATTERY TEMPERATURESENSORAIR INLETTUBE

PL FUEL SYSTEM 14 - 47

DIAGNOSIS AND TESTING (Continued)

(24) Inspect the connections to the speed control
servo, if equipped (Fig. 54). Refer to Group 8H, Vehi­cle Speed Control.

Fig. 76 Battery Temp. Sensor Connectors

(25) Inspect the connection at the battery temper­ature sensor (Fig. 76).

ASD AND FUEL PUMP RELAYS

RELAY TERMINALSRELAY CAVITIES

The following description of operation and
tests apply only to the Automatic Shutdown
(ASD) and fuel pump relays . The terminals on

the bottom of each relay are numbered (Fig. 77).

• The Powertrain Control Module (PCM) grounds

the coil side of the relay through terminal number

85.

• Terminal number 86 supplies voltage to the coil

side of the relay.

• When PCM de-energizes the ASD and fuel pump
relays, terminal number 87A connects to terminal 30.
This is the Off position. In the off position, voltage is
not supplied to the rest of the circuit. Terminal 87A
is the center terminal on the relay. There is no wire
or terminal in the cavity.

• When the PCM energies ASD and fuel pump
relays energize, terminal 87 connects to terminal 30.
This is the On position. Terminal 87 supplies voltage
to the rest of the circuit.

TESTING

The following procedure applies to the ASD and

fuel pump relays.

(1) Remove relay from connector before testing.

(2) With the relay removed from the vehicle, use
an ohmmeter to check the resistance between termi­nals 85 and 86 of the relay. The resistance should be
between 75 65 ohms.

(3) Connect the ohmmeter between relay terminals
30 and 87A of the relay. The ohmmeter should show
continuity between terminals 30 and 87A.

(4) Connect the ohmmeter between relay terminals
87 and 30 of the relay. The ohmmeter should not
show continuity at this time.

(5) Connect one end of a jumper wire (16 gauge or
heavier) to relay terminal 85. Connect the other end
of the jumper wire to the ground side of a 12 volt
power source.

(6) Connect one end of another jumper wire (16
gauge or heavier) to the power side of the 12 volt
power source. Do not attach the other end of the

jumper wire to the relay at this time.

Fig. 77 ASD and Fuel Pump Relay Terminals

OPERATION

• Terminal number 30 is connected to battery volt­age. For both the ASD relay and fuel pump relays,
terminal 30 is connected to battery voltage at all
times.

WARNING: DO NOT ALLOW OHMMETER TO CON­TACT TERMINALS 85 OR 86 DURING THIS TEST.

(7) Attach the other end of the jumper wire to
relay terminal 86. This activates the relay. The ohm­meter should now show continuity between relay ter­minals 87 and 30. The ohmmeter should not show
continuity between relay terminals 87A and 30.

(8) Disconnect jumper wires.

(9) Replace the relay if it did not pass the continu­ity and resistance tests. If the relay passed the tests,
it operates properly. Check the remainder of the ASD
and fuel pump relay circuits. Refer to group 8W, Wir­ing Diagrams.

CAMSHAFT AND CRANKSHAFT POSITION SENSOR

Refer to Group 8D, Ignition for Diagnosis and Test­ing of Camshaft and Crankshaft Sensors.

14 - 48 FUEL SYSTEM PL

DIAGNOSIS AND TESTING (Continued)

ENGINE COOLANT TEMPERATURE SENSOR

(1) With the key off, disconnect wire harness con­nector from coolant temperature sensor (Fig. 78) or
(Fig. 79).

Fig. 80 Engine Coolant Temperature Sensor

greater than 1 ohm, repair the wire harness as nec­essary.

Fig. 78 Engine Coolant Temperature Sensor

Location—SOHC

Fig. 79 Engine Coolant Temperature Sensor

Location—DOHC

(2) Connect a high input impedance (digital) volt­ohmmeter to terminals A and B (Fig. 80). The ohm­meter should read as follows:

• Engine/Sensor at normal operating temperature
around 200°F should read approximately 700 to
1,000 ohms.

• Engine/Sensor at room temperature around 70°F
ohmmeter should read approximately 7,000 to 13,000
ohms.

(3) Test the resistance of the wire harness between
the PCM 60-way connector terminal 28 and the sen­sor harness connector. Also check for continuity
between PCM 60-way connector terminal 51 and the
sensor harness connector. Refer to Group 8W, Wiring
diagrams for circuit information. If the resistance is

HEATED OXYGEN SENSOR

Use an ohmmeter to test the heating element of
the oxygen sensors. Disconnect the electrical connec­tor from each oxygen sensor. The white wires in the
sensor connector are the power and ground circuits
for the heater. Connect the ohmmeter test leads to
terminals of the white wires in the heated oxygen
sensor connector. Replace the heated oxygen sensor if
the resistance is not between 4 and 7 ohms.

IDLE AIR CONTROL (IAC) MOTOR TEST

To preform a complete test of IAC motor and its
circuitry, refer to DRB scan tool and the appropriate
Powertrain Diagnostics Procedures manual.

KNOCK SENSOR

The knock sensor can be tested with a digital volt­meter. Sensor output should be between 80 mV and 4
volts with the engine running between 576 and 2208
rpm. If the output falls outside of this range a DTC
will be set.

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR

To perform a complete test of the MAP sensor and
its circuitry, refer to the DRB scan tool and appropri­ate Powertrain Diagnostics Procedures manual. To
test the MAP sensor only, refer to the following:

CAUTION: When testing the MAP sensor, be sure
that the harness wires are not damaged by the test
meter probes.

(1) Test the MAP sensor output voltage at the
MAP sensor connector between terminals 1 and 4
(Fig. 81). With the ignition switch ON and the engine
not running, output voltage should be 4 to 5 volts.

SENSOR GROUNDIAT OUTPUT VOLTAGEVOLTAGE SUPPLYMAP OUTPUT VOLTAGE

THROTTLEBODY

PCV VALVECONNECTION TOINTAKE MANIFOLDINTAKE MANI-FOLD

PURGE

HOSE

PL FUEL SYSTEM 14 - 49

DIAGNOSIS AND TESTING (Continued)

The voltage should drop to 1.5 to 2.1 volts with a hot,
neutral idle speed condition. If OK, go to next step. If
not OK, go to step 3.

Wide-Open-Throttle (WOT). At idle, TPS output volt­age should be approximately 0.38 volts to 1.2 volts.
At wide open throttle, TPS output voltage should be
approximately 3.1 volts to 4.4 volts. The output volt­age should gradually increase as the throttle plate
moves slowly from idle to WOT.

Check for spread terminals at the sensor and PCM
connections before replacing the TPS.

THROTTLE BODY MINIMUM AIR FLOW

(1) Turn ignition key to Off.

(2) Disconnect the PCV valve hose from the intake
manifold nipple (Fig. 82). Cap the PCV vacuum nip­ple.

Fig. 81 MAP Sensor Connector

(2) Test PCM terminal 36 for the same voltage
described in the previous step to verify wire harness
condition. Repair as required.

(3) Test the MAP sensor ground circuit at sensor
connector terminal 1 and PCM terminal 43. If OK, go
to next step. If not OK, repair as required.

(4) Test MAP sensor supply voltage between sen­sor connector terminals 3 and 1 with the key ON.
The voltage should be approximately 5 volts (6.5V).
Five volts (6.5V) should also be at terminal 61 of the
PCM. If OK, replace MAP sensor. If not OK, repair or
replace the wire harness as required.

THROTTLE POSITION SENSOR

To perform a complete test of the this sensor and
its circuitry, refer to the DRB scan tool and appropri­ate Powertrain Diagnostics Procedures manual. To
test the throttle position sensor only, refer to the fol­lowing:

The Throttle Position Sensor (TPS) can be tested
with a digital voltmeter (DVM). The center terminal
of the sensor is the output terminal. One of the other
terminals is a 5 volt supply and the remaining ter­minal is ground.

Connect the DVM between the center and sensor
ground terminal. Refer to Group 8W - Wiring Dia­grams for correct pinout.

With the ignition switch in the ON position, check
the output voltage at the center terminal wire of the
connector. Check the output voltage at idle and at

Fig. 82 PCV Vacuum Nipple

(3) Disconnect purge hose from the nipple on the

throttle body (Fig. 83).

Fig. 83 Purge Hose

SPECIALTOOL #6457PURGE NIP-PLE

14 - 50 FUEL SYSTEM PL

SPEED CONTROLCABLE THROTTLECABLETHROTTLELEVER

DIAGNOSIS AND TESTING (Continued)

(4) Use a piece of hose to attach Air Metering Ori­fice 6457 (0.125 in. orifice) to the purge nipple on the
throttle body (Fig. 84).

Fig. 84 Orifice 6457 Attached to Purge Nipple

(5) Ensure that all accessories are off.

(6) Connect the DRB scan tool to the data link
connector inside the passenger compartment.

(7) Run engine in Park or Neutral until the cooling
fan has cycled on and off at least once (180°F).

(8) Using the DRB scan tool, access Minimum Air­flow Idle Speed.

(9) The following will then occur:

• Idle air control motor will fully close

• Idle spark advance will become fixed

• PCM will go open loop enriched

• DRB scan tool displays engine RPM

(10) If idle RPM is within the range shown in the
Idle Specification chart, throttle body minimum air­flow is set correctly.

IDLE SPECIFICATION —2.0L ENGINE

Odometer Reading Idle RPM

Below 1000 Miles ...............550–1300 RPM

Above 1000 Miles ...............600–1300 Miles

(b) While holding the throttle open, spray the
entire throttle body bore and the manifold side of
the throttle plate with Mopar Parts Cleaner. Only

use Mopar Parts Cleaner to clean the throttle
body.

(c) Using a soft scuff pad, clean the top and bot­tom of throttle body bore and the edges and mani­fold side of the throttle blade. The edges of the

throttle blade and portions of the throttle
bore that are closest to the throttle blade
when closed, must be free of deposits.

(d) Use compressed air to dry the throttle body.

(e) Inspect throttle body for foreign material.

(f) Install throttle body on manifold.

(g) Repeat steps 1 through 14. If the minimum
air flow is still not within specifications, the prob­lem is not caused by the throttle body.
(12) Shut off engine.
(13) Remove Air Metering Orifice 6457. Install

purge hose.

(14) Remove cap from PCV valve. Connect hose to

PCV valve.

(15) Remove DRB scan tool.

VEHICLE SPEED SENSOR

To perform a complete test of the sensor and its

circuitry, refer to the DRB scan tool and appropriate
Powertrain Diagnostics Procedures Manual.

REMOVAL AND INSTALLATION

THROTTLE BODY—MANUAL TRANSMISSION

Remove throttle body cables using the following

procedures.

REMOVAL

(1) Remove throttle cable cover.
(2) Remove throttle cable from the throttle body

cam (Fig. 85) and (Fig. 86).

(11) If idle RPM is above specifications, use the
DRB scan tool to check idle air control motor opera­tion. If idle air control motor is OK, replace throttle
body. If idle air flow is below specification, shut off
the engine and clean the throttle body as follows:

WARNING: CLEAN THROTTLE BODY IN A WELL
VENTILATED AREA. WEAR RUBBER OR BUTYL
GLOVES, DO NOT LET MOPAR PARTS CLEANER
COME IN CONTACT WITH EYES OR SKIN. AVOID
INGESTING THE CLEANER. WASH THOROUGHLY
AFTER USING CLEANER.

(a) Remove the throttle body from engine.

Fig. 85 Throttle Cable Attachment to Throttle Body

CLASP

TABSCABLE

SPEED CON-TROL CABLE THROTTLECABLETRANSMISSIONKICKDOWNCABLE

TABSCABLECLASP

PL FUEL SYSTEM 14 - 51

REMOVAL AND INSTALLATION (Continued)

(2) Remove throttle body cables using the following

procedures.

(3) Remove throttle cable from throttle body cam

(Fig. 87) and (Fig. 88).

Fig. 86 Disconnecting Throttle Cable

(3) Compress the retaining tabs on the cable and
slide cable out of bracket (Fig. 86).

(4) If equipped with speed control, remove speed
control cable from throttle lever by sliding clasp out
hole used for throttle cable.

(5) Remove 2 screws holding cable mounting
bracket and support bracket.

(6) Remove TPS connector.

(7) Remove Idle Air Control motor connector.

(8) Remove the EVAP purge hose.

(9) Remove throttle body mounting bolts. Remove
throttle body.

(10) The rubber O-ring gasket on the intake man­ifold is reusable. Wipe the O-ring clean before install­ing throttle body (Fig. 91).

Fig. 87 Throttle Body Cables Attachment to Throttle

Body

INSTALLATION

(1) Install throttle body on intake manifold.
Tighten mounting bolts.

(2) Attach cable mounting bracket and support
bracket with 2 screws.

(3) Connect the electrical connetion to the throttle
body.

(4) Connect the EVAP purge hose to the throttle
body.

(5) Install cable housing(s) retainer tabs into
bracket.

(6) If equipped with speed control, rotate the throt­tle lever forward to the wide open position and
install speed control cable clasp (Fig. 86).

(7) Rotate throttle lever to wide open position and
install throttle cable clasp (Fig. 86).

(8) Install throttle cable cover. Tighten bolt to 5.6
N·m (50 ins. lbs.).

THROTTLE BODY—AUTOMATIC TRANSMISSION

REMOVAL

(1) Remove throttle cable cover.

Fig. 88 Disconnecting Throttle Cable

(4) Compress the retaining tabs on the cable and

slide cable out of bracket (Fig. 88).

(5) Hold throttle lever in the wide open position.
Using finger pressure only, remove kickdown cable by
PUSHING connector off the lever nail head (Fig. 87)
and (Fig. 89). DO NOT try to pull connector off per­pendicular to the lever.

(6) Compress the retaining tabs on the cable and
slide cable out of bracket (Fig. 88).

(7) if equipped with speed control, hold throttle
lever in the wide open position. Using finger pressure
only, remove speed control cable by PUSHING con­nector off the lever nail head (Fig. 87) and (Fig. 90).
DO NOT try to pull connector off perpendicular to
the lever.

PUSHSPEED CONTROL CABLE

PUSHTRANSMISSION KICK-DOWN CABLE

INTAKEMANIFOLD

THROTTLEPOSITIONSENSOR

RE-USABLE

IDLE AIR CON-

GASKET

TROL MOTOR

14 - 52 FUEL SYSTEM PL

REMOVAL AND INSTALLATION (Continued)

Fig. 89 Transmission Kickdown Cable Connector

Fig. 90 Speed Control Cable Connector

(8) Compress the retaining tabs on the cable and

slide cable out of bracket (Fig. 88).

(9) Remove 2 screws holding cable mounting

bracket and support bracket.

(10) Remove TPS connector.
(11) Remove Idle Air Control motor connector.
(12) Remove EVAP purge hose.
(13) Remove throttle body mounting bolts. Remove

throttle body.

(14) The rubber O-ring gasket on the intake man­ifold is reusable. Wipe the O-ring clean before install­ing throttle body (Fig. 91).

Fig. 91 Re-Usable Throttle Body Gasket

(6) Install throttle body cables using the following

procedures.

(7) From the engine compartment, rotate the
throttle lever forward to the wide open position and
install throttle cable clasp (Fig. 88).

(8) If equipped with speed control, rotate throttle
lever forward to the wide open position and slide
speed control cable connector onto nail head.

(9) Rotate throttle lever forward to the wide open
position and slide kickdown cable connector onto nail
head.

(10) Install throttle cable cover. Tighten bolt to 5.6
N·m (50 ins. lbs.).

THROTTLE POSITION SENSOR (TPS)

The throttle position sensor attaches to the side of
the throttle body (Fig. 92).

INSTALLATION

(1) Install throttle body on intake manifold.

Tighten mounting bolts.

(2) Attach cable mounting bracket and support

bracket with 2 screws.

(3) Connect electrical connection to throttle body.
(4) Connect the EVAP purge hose.
(5) Install cable housing(s) retainer tabs into

bracket.

Fig. 92 Throttle Position Sensor and Idle Air Control

Motor

REMOVAL

(1) Disconnect EVAP purge hose from throttle body.

PL FUEL SYSTEM 14 - 53

REMOVAL AND INSTALLATION (Continued)

(2) Disconnect electrical connector from idle air

control motor and throttle position sensor.

(3) Remove throttle body. Refer to Throttle Body in

this section.

(4) Remove throttle position sensor mounting screws.
(5) Remove throttle position sensor.

INSTALLATION

(1) The throttle shaft end of the throttle body slides
into a socket in the TPS (Fig. 93). The socket has two
tabs inside it. The throttle shaft rests against the
tabs. When indexed correctly, the TPS can rotate
clockwise a few degrees to line up the mounting screw
holes with the screw holes in the throttle body. The
TPS has slight tension when rotated into position. If it
is difficult to rotate the TPS into position, install the
sensor with the throttle shaft on the other side of the
tabs in the socket. Tighten mounting screws to 2 N·m
(17 in. lbs.) torque.

(2) Remove electrical connector from idle air con-

trol motor and throttle position sensor.

(3) Remove the EVAP purge hose from the throttle

body.

(4) Remove throttle body. Refer to Throttle Body in

this section.

(5) Remove idle air control motor mounting screws

(Fig. 94).

Fig. 93 Throttle Position Sensor Installation

(2) After installing the TPS, the throttle plate
should be closed. If the throttle plate is open, install
the sensor on the other side of the tabs in the socket.

(3) Install throttle body. Refer to Throttle Body in
this section.

(4) Attach electrical connectors to idle air control
motor and throttle position sensor.

(5) Install EVAP purge hose to throttle body nipple.

IDLE AIR CONTROL MOTOR

When servicing throttle body components, always
reassemble components with new O-rings and seals
where applicable. Never use lubricants on O-rings or
seals, damage may result. If assembly of component is
difficult, use water to aid assembly. Use care when
removing hoses to prevent damage to hose or hose
nipple.

REMOVAL

(1) Disconnect negative cable from battery.

Fig. 94 Servicing Idle Air Control Motor

(6) Remove motor from throttle body. Ensure the

O-ring is removed with the motor.

INSTALLATION

(1) The new idle air control motor has a new
O-ring installed on it. If pintle measures more than 1
inch (25 mm) it must be retracted. Use the DRB Idle
Air Control Motor Open/Close Test to retract the
pintle (battery must be connected.)

(2) Carefully place idle air control motor into
throttle body.

(3) Install mounting screws. Tighten screws to 2
N·m (17 in. lbs.) torque.

(4) Install throttle body. Refer to Throttle Body in
this section.

(5) Connect electrical connector to idle air control
motor and throttle position sensor.

(6) Connect the EVAP purge hose to the throttle
body nipple.

(7) Connect negative cable to battery.

MAP/IAT SENSOR—SOHC

The MAP/IAT sensor attaches to the intake mani­fold plenum (Fig. 95).

REMOVAL

(1) Disconnect the electrical connector from the
MAP/IAT sensor.

(2) Remove sensor mounting screws.

(3) Remove sensor.

14 - 54 FUEL SYSTEM PL

REMOVAL AND INSTALLATION (Continued)

INSTALLATION

(1) Insert sensor into intake manifold while mak-

ing sure not to damage O-ring seal.

(2) Tighten mounting screws to 2 N·m (20 in. lbs)
torque for plastic manifold and 3 N·m (30 in. lbs.) for
aluminum manifold.

(3) Attach electrical connector to sensor.

Fig. 95 MAP/IAT Sensor—SOHC

(2) Disconnect the electrical connector from the

MAP/IAT sensor.

(3) Remove sensor mounting screws.
(4) Remove sensor.

INSTALLATION

(1) Insert sensor into intake manifold while mak-

ing sure not to damage O-ring seals.

(2) Tighten mounting screws to 2 N·m (20 in. lbs)
torque foe a plastic manifold and 3 N·m (30 in. lbs)
for a aluminum manifold.

(3) Attach electrical connector to sensor.

(4) Install air inlet duct wing nut and duct from
intake manifold, insure that the duct does not inter­fer with ignition cables.

MAP/IAT SENSOR—DOHC

The MAP/IAT sensor attaches to the intake mani-

fold plenum (Fig. 97).

REMOVAL

(1) Remove air inlet duct wing nut and duct from

intake manifold (Fig. 96).

WING NUTAIR INLETDUCT

Fig. 97 MAP/IAT Sensor—DOHC

DUTY CYCLE EVAP PURGE SOLENOID VALVE

The solenoid attaches to a bracket near the front
engine mount (Fig. 98). The solenoid will not operate
unless it is installed correctly.

REMOVAL

(1) Disconnect electrical connector from solenoid.

(2) Disconnect vacuum tubes from solenoid.

(3) Remove solenoid from bracket.

INSTALLATION

The top of the solenoid has TOP printed on it. The
solenoid will not operate unless it is installed cor­rectly.

(1) Install solenoid on bracket.

(2) Connect vacuum tube to solenoid.

(3) Connect electrical connector to solenoid.

Fig. 96 Air Inlet Duct—DOHC

POWERTRAIN CONTROL MODULE (PCM)

The PCM attaches to the inner fender panel next
to the washer fluid bottle on the passenger side (Fig.

99).

DUTY CYCLE EVAPPURGE SOLENOIDVALVE ENGINEMOUNT

SPEED CON-TROL SERVO WINDSHIELDWASHER FLUIDBOTTLEPCMBATTERYPOWER DISTRI-BUTION CEN-TER

PL FUEL SYSTEM 14 - 55

REMOVAL AND INSTALLATION (Continued)

(3) Install PDC by pushing down into brackets.

(4) Install washer bottle neck.

(5) Connect positive cable to battery.

(6) Connect negative cable to battery.

CRANKSHAFT POSITION SENSOR

For removal/installation procedures refer to group
8D - Ignition System, Service Procedures.

CAMSHAFT POSITION SENSOR

For removal/installation procedures refer to group
8D - Ignition System, Service Procedures.

UPSTREAM HEATED OXYGEN SENSOR

REMOVAL

(1) Raise and support vehicle.

(2) Unplug sensor connector.

(3) Remove sensor using an oxygen sensor crow
foot wrench such as Snap-On tool YA8875 or equiva­lent (Fig. 100).

(4) After removing the sensor, the exhaust mani­fold threads must be cleaned with an 18 mm X 1.5 +

Fig. 98 Duty Cycle EVAP Purge Solenoid Valve

REMOVAL

(1) Disconnect negative cable from battery.
(2) Disconnect positive cable from battery.
(3) Remove washer bottle neck.

(4) Squeeze tabs on PDC while pulling PDC up to
remove it from bracket. Lay PDC aside to gain access
to PCM bracket screws.

(5) Remove screws attaching PCM to body.

(6) Lift PCM up and disconnect the 2 40-way con­nector.

(7) Remove PCM.

6E tap. If reusing the original sensor, coat the sensor
threads with an anti-seize compound such as Loctitet
771-64 or equivalent.

INSTALLATION

New sensors have compound on the threads and do

not require an additional coating.

(1) Install sensor using an oxygen sensor crow foot

EXHAUSTPIPEFLANGE CROW FOOTWRENCHUPSTREAMOXYGEN SEN-SOR

wrench such as Snap-On tool YA8875 or equivalent
(Fig. 100). Tighten the sensor to 28 N·m (20 ft. lbs.)
torque.

(2) Plug sensor connector.
(3) Lower vehicle.

Fig. 99 Powertrain Control Module

INSTALLATION

(1) Attach the 2 40-way connector to PCM.

(2) Install PCM. Tighten mounting screws to 9
N·m (80 in. lbs.) torque.

Fig. 100 Upstream Heated Oxygen Sensor Removal/

Installation

DOWNSTREAMHEATED OXYGENSENSOR CATALYTICCONVERTOR

14 - 56 FUEL SYSTEM PL

REMOVAL AND INSTALLATION (Continued)

DOWNSTREAM HEATED OXYGEN SENSOR

The downstream heated oxygen sensor threads into
the exhaust outlet pipe behind the catalytic convertor
(Fig. 101).

REMOVAL

(1) Raise vehicle.

(2) Disconnect electrical connector from sensor.

(3) Disconnect sensor electrical harness from clips
along body.

(4) Remove sensor using an oxygen sensor crow
foot wrench such as Snap-On tool YA8875 or equiva­lent (Fig. 102).

(5) After removing the sensor, the exhaust mani­fold threads must be cleaned with an 18 mm X 1.5 +
6E tap. If reusing the original sensor, coat the sensor
threads with an anti-seize compound such as Loctitet
771-64 or equivalent.

INSTALLATION

New sensors have compound on the threads and do
not require an additional coating.

(1) Install sensor using an oxygen sensor crow foot
wrench such as Snap-On tool YA8875 or equivalent
(Fig. 102). Tighten the sensor to 28 N·m (20 ft. lbs.)
torque.

(2) Connect sensor electrical harness from clips
along body.

(3) Connect electrical connector from sensor.

(4) Lower vehicle.

Fig. 102 Downstream Heated Oxygen Sensor

Removal/Installation

REMOVAL

(1) Remove air intake tube (Fig. 103) from air

cleaner and intake manifold (Fig. 104).

Fig. 101 Downstream Heated Oxygen Sensor

AIR CLEANER ELEMENT

Neon vehicles do not use a heated air inlet system.
The PCM adjusts fuel injector pulse width and igni­tion timing to compensate for different ambient tem­peratures.

The air cleaner attaches to a bracket on the rear of
the cylinder head. An ambient air duct supplies
underhood air for the engine.

AIR INLET DUCT

Fig. 103 Air Intake Duct

Fig. 104 Removal/Installation of Air Inlet Duct

AIR CLEANER

PL FUEL SYSTEM 14 - 57

REMOVAL AND INSTALLATION (Continued)

(2) Unfasten clasps on top of air cleaner housing.
Rotate front of housing forward then lift front away
from air cleaner housing (Fig. 105).

Fig. 105 Removal/Installation Air Cleaner Front

Housing and Element

(3) Remove air cleaner element from front housing
(Fig. 105).

INSTALLATION

(1) Install air cleaner element into front housing.

(2) Rotate front of housing forward then lower into
place and locate tabs in slots. Fasten clasps on top of
air cleaner housing.

(3) Install air intake duct at air cleaner and intake
manifold.

INSTALLATION

(1) Install coolant sensor. Tighten sensor to 18

ENGINE COOLANTTEMPERATURESENSORCAMSHAFTPOSITIONSENSOR

FUEL RAIL

COOLANT TEMPER-ATURE SENSOR

N·m (165 in. lbs.) torque.

(2) Attach electrical connector to sensor.
(3) Fill cooling system. Refer to Group 7, Cooling

System.

Fig. 106 Engine Coolant Temperature Sensor—

SOHC

ENGINE COOLANT TEMPERATURE SENSOR

The engine coolant temperature sensor threads
into the rear of the cylinder head (Fig. 106) or (Fig.

107).

REMOVAL

(1) With the engine cold, drain coolant until level
drops below cylinder head. Refer to Group 7, Cooling
System.

(2) Disconnect coolant sensor electrical connector.

(3) Remove coolant sensor.

Fig. 107 Engine Coolant Temperature Sensor—

DOHC

TRANSAXLE SPEEDSENSORSPEED SENSOR RETAININGBOLT

14 - 58 FUEL SYSTEM PL

REMOVAL AND INSTALLATION (Continued)

VEHICLE SPEED SENSOR

The vehicle speed sensor is located in the transmis­sion extension housing (Fig. 108).

REMOVAL

(1) Disconnect electrical connector from sensor.

(2) Remove the sensor mounting bolt.

(3) Lift the sensor out of the transaxle extension
housing. Ensure the O-ring was removed with the
sensor.

INSTALLATION

The speed sensor gear meshes with a gear on the
output shaft.

(1) With O-ring in place, install sensor.

(2) Install mounting bolt.

(3) Connect electrical connector to sensor.

Fig. 108 Vehicle Speed Sensor

KNOCK SENSOR

For removal/installation procedures refer to Group

8D- Ignition System, Service Procedures.

SPECIFICATIONS

VECI LABEL

If anything differs between the specifications found
on the Vehicle Emission Control Information (VECI)
label and the following specifications, use specifica­tions on VECI label. The VECI label is located in the
engine compartment.

TORQUE SPECIFICATIONS

DESCRIPTION TORQUE

Air Cleaner Wingnut .........1.5N·m(15in.lbs.)

Air Cleaner Mount. Stud-To-

Thrott. Body .............10N·m(90in.lbs.)

Crankshaft Position Sensor

Mounting Bolts ............8N·m(70in.lbs.)

Engine Coolant Temperature

Sensor .................18N·m(165 in. lbs.)

IAC Motor-To-Throttle Body

Bolts ....................7N·m(60in.lbs.)

MAP/IAT Sensor .............2N·m(20in.lbs.)

MAP/IAT Sensor .............3N·m(30in.lbs.)

Oxygen Sensor ..............28N·m(20ft.lbs.)

Powertrain Control Module

(PCM) Mounting Screws .....4N·m(35in.lbs.)

Throttle Body Mounting Bolts . 23 N·m (200 in. lbs.)
Throttle Position Sensor

Mounting Screws ...........2N·m(20in.lbs.)

Vehicle Speed Sensor

Mounting Bolt ............2.2N·m(20in.lbs.)

PL FUEL SYSTEM 14 - 59

SPECIAL TOOLS

FUEL

Spanner Wrench 6856

Extractor C–4334

Metering Orifice

Pressure Gauge Assembly C–4799–B

Fuel Pressure Test Adapter 6539

Fuel Line Tool

Fuel Line Adapter

14 - 60 FUEL SYSTEM PL

SPECIAL TOOLS (Continued)

Fuel Line Adapter 1/4