Equus 3123 User Manual

GM



Innova 1998

GM CODE READER 1.6

SAVE TIME AND MONEY BY

IDENTIFYING ENGINE PROBLEMS YOURSELF

• COMPUTER SAFE

• NO BATTERY REQUIRED

FOR GENERAL MOTORS AND SATURN

VEHICLES FROM 1982 TO 1995

(EXCLUDING CADILLAC)

Table of Contents

i GM

Paragraph Title Page No.

YOU CAN DO IT! ........................................................ ii

GENERAL INFORMATION

1.1 YOUR VEHICLE'S COMPUTER SYSTEM............... 1-1

1.2 ABOUT YOUR CODE READER................................. 1-2

1.3 TEST CONNECTOR LOCATIONS ............................ 1-2

1.4 SAFETY PRECAUTIONS........................................... 1-3

1.5 VEHICLE SERVICE MANUALS ............................... 1-3

1.6 PRELIMINARY VEHICLE DIAGNOSIS .................. 1-4

WORKSHEET

RETRIEVING ECM CODES

2.1 VEHICLES COVERED ............................................... 2-1

2.2 BEFORE YOU BEGIN ............................................... 2-2

2.3 RETRIEVING SERVICE CODES ............................. 2-3

2.4 ERASING SERVICE CODES ..................................... 2-6

2.5 ECM SERVICE CODES.............................................. 2-6

RETRIEVING ABS CODES

3.1 ANTI-LOCK BRAKE SYSTEMS ................................ 3-1

3.2 APPLICATIONS ......................................................... 3-1

3.3 RETRIEVING SERVICE CODES ............................. 3-2

3.4 ERASING SERVICE CODES ..................................... 3-7

3.5 ABS SERVICE CODES............................................... 3-9

GLOSSARY

4.1 INTRODUCTION ........................................................ 4-1

4.2 GLOSSARY OF TERMS AND ................................... 4-1

ABBREVIATIONS

WARRANTY AND SERVICE

5.1 LIMITED ONE YEAR WARRANTY .......................... 5-1

5.2 SERVICE PROCEDURES .......................................... 5-1

You Can Do It!

GM ii

Plug It In

•

Test connector usually found
under the left side of the
dashboard.

•

Set Selector switch to ECM A-B
position.

•

Make sure ignition is off. Plug
Code Reader into test connector.

Read Fault Codes

•

Turn on ignition. DO NOT

START ENGINE.

•

Read codes from flashing
"Check Engine" or "Service

Engine Soon" light.

Pinpoint Problems

•

Locate fault code(s) in the
appropriate Service Codes List.

1

CHECK ENGINECHECK ENGINE

SERVICESERVICE

ENGINEENGINE

SOONSOON

2

3

CODE DEFINITION

el Injector circuit is not working p

Ignition system fault - Intermittent 7X sign

loss of 58X signal or 6X signal (Saturn)

1 Throttle position sensor (TPS) - signal voltag

high during engine idle or deceleration

22 Throttle position sensor (TPS) - signal

low during engine idle

Fuel cutoff relay circuit - open

ground

23 Manifold air temperature (M

voltage is low or high

Throttle position senso

Mixture Control (M

circuit problems

Intake Air T

Vehicle sp

problem

Read manual for a complete description of the Code Reader and
it's proper use and operation.

1

1-1 GM

1.1 YOUR VEHICLE'S COMPUTER SYSTEM

Today's vehicles are equipped with computer self-testing
abilities that can locate problems in your vehicle and store
them as service codes in the vehicle's onboard computer. The
Code Reader allows you access to the computer's memory and
recalls the service codes.

1.1.1 Instrument Panel Indicator Lights

Your vehicle's Instrument panel has several indicator lights, such
as the "Check Engine", "Service Engine Soon", "ABS", "Shift to
D2" and "Temperature" indicator lights. These lights do more
than tell you to check for engine, brake, or other component
malfunctions. They can also transmit the service codes in the
computer memory by blinking on and off.

NOTE:

If your instrument panel indicator lights do not come
on when you turn on the ignition, please refer to your
vehicle's service manual. You may have problems in
the car's circuitry. You must fix these problems before
you can obtain service codes from the vehicle's
onboard computer.

1.1.2 Service Codes

The service codes are also called "fault codes", "diagnostic
codes" or "trouble codes". These codes can be used to identify
systems or components which are malfunctioning.

The computer records codes for two types of problems:

"Hard" Codes. "Hard" codes are stored for problems
which are happening now. The instrument panel indicator
light will stay on when the engine is running.

■ "Intermittent" Codes or "Continuous Memory" Codes.

Intermittent service codes are stored in the computer's
memory for problems which occur intermittently, or for
problems which happened in the past but are not currently
present. Intermittent problems may cause the panel
indicator light to flicker or to turn on intermittently.
Intermittent codes are stored in the computer's memory for
a set period of time (usually 50 start cycles). If an
intermittent problem does not recur within this time
period, the computer automatically erases the related
intermittent fault code from it's memory.

CHECK ENGINECHECK ENGINE

SERVICESERVICE

ENGINEENGINE

SOONSOON

■

General Information

GM 1-2

NOTE :

For Saturn vehicles, either the "Shift to D2" light or
the "Temperature" indicator light is used to transmit
Saturn Electronic Transmission codes.

1.2 ABOUT YOUR CODE READER

The Code Reader is a device which connects to your vehicle's
computer self-test connector. It allows the computer to output
the service codes through the vehicle's instrument panel
indicator lights. The Code Reader can be used to retrieve:

■ Engine/Electronic Transmission codes (ECM/PCM)

NOTE:

Unless otherwise indicated, any reference to ECM
throughout this manual also applies to PCM.

■ Anti-Lock Brake System codes (ABS)

1.2.1 Controls and Indicators

Selector Switch – Selects
operating mode for Code Reader:

■ ECM A-B – Use to retrieve ECM

codes

■ ABS A-H – Use to retrieve ABS

service codes

1.3 TEST CONNECTOR LOCATIONS

•

The gateway to your vehicle's onboard computer.

Your vehicle test connector also
known as the Assembly Line Data
Link (ALDL) connector or Assembly
Line Communication Link (ALCL)
connector is usually black in color
and is most likely found under the left side of the dashboard.
Some connectors can be found on the right kick panel, under
the center of the dashboard, on the side of the fuse block or
under the ashtray in the center console. The connector might
have a plastic cover on it labeled "Diagnostic Connector". If
you have any questions about the connector's location, please
refer to your vehicle's service manual for detailed information.

1

1-3 GM

1.4 SAFETY PRECAUTIONS

•

Always observe safety precautions whenever working on a
vehicle.

a. Always wear safety eye protection.
b. Only work on your vehicle in a well-ventilated area.
c. Put transmission in “park” (for automatic) or “neutral” (for

manual). Set parking brake.

d. Put blocks on drive wheels.
e. Avoid moving fan blades or any potentially moving parts.
f. Avoid hot engine parts.
g. Turn off ignition before connecting (or disconnecting) any

testing equipment.

h. Please read your vehicle’s service manual and follow it’s

safety procedure.

1.5 VEHICLE SERVICE MANUALS

It is recommended that you consult
the manufacturer’s instructions and
specifications in these service man­uals before any test or tune-up
procedures are performed.

IMPORTANT: You MUST use the
wiring diagrams in your vehicle's

service manual to ensure proper
connections during testing.

Contact your local car dealership, auto parts store, bookstore
or public library for availability of these manuals. The
following companies publish valuable repair manuals:

■ General Motors Publications, Helm, Inc., 14310 Hamilton

Ave., Highland Park, MI 48203, Phone: [phone]

■ Haynes Publications, 861 Lawrence Drive, Newbury Park,

California 91320, Phone: [phone], Fax: (805) 498­2867

■ Mitchell International, 14145 Danielson St., Poway,

California 92064, Phone: [phone]

■ Motor Publications, 5600 Crooks Road, Troy, Michigan

48098, Phone: [phone], Fax: [phone]

F8

PNK-BLK PNK-BLK

F/P FUSE

DK GRN-WHT

BLK-WHT

PNK-BLK

GRY
RED

FUEL PUMP

PRIME CONN

FUEL PUMP

6
2
4
1
3

TYPICAL WIRING

DIAGRAM

General Information

GM 1-4

1.6 PRELIMINARY VEHICLE DIAGNOSIS WORKSHEET

The purpose of this form is to help you gather preliminary information
on your vehicle before you retrieve codes. By having a complete
account of your vehicle's current problem(s), you will be able to
systematically pinpoint the problem(s) by comparing your answers to
the fault codes you retrieve. You can also provide this information to
your mechanic to assist in diagnosis and help avoid costly and
unnecessary repairs. It is important for you to complete this form to help
you and/or your mechanic have a clear understanding of your vehicle's
problems.

NAME:
DATE:
VIN*:
YEAR:
MAKE:
MODEL:
ENGINE SIZE:
VEHICLE MILEAGE:

*VIN: Vehicle Identification Number, found at the base of the
windshield on a metallic plate, or at the driver door latch area (consult
your vehicle owner's manual for location).

TRANSMISSION:

❑ Automatic
❑ Manual

Please check all applicable items in each category.

DESCRIBE THE PROBLEM:

1

1-5 GM

WHEN DID YOU FIRST NOTICE THE PROBLEM:

❑ Just Started
❑ Started Last Week
❑ Started Last Month
❑ Other:

LIST ANY REPAIRS DONE IN THE PAST SIX MONTHS:

PROBLEMS STARTING

ENGINE QUITS OR STALLS

IDLING CONDITIONS

RUNNING CONDITIONS

❑ No symptoms
❑ Will not crank

❑ Cranks, but will not start
❑ Starts, but takes a long time

❑ No symptoms
❑ Right after starting
❑ When shifting into gear
❑ During steady-speed driving

❑ Right after vehicle comes to a stop
❑ While idling
❑ During acceleration
❑ When parking

❑ No symptoms
❑ Is too slow at all times
❑ Is too fast

❑ Is sometimes too fast or too slow
❑ Is rough or uneven
❑ Fluctuates up and down

❑ No symptoms
❑ Runs rough
❑ Lacks power
❑ Bucks and jerks
❑ Poor fuel economy
❑ Hesitates or stumbles on

accelerations

❑ Backfires
❑ Misfires or cuts out
❑ Engine knocks, pings or rattles
❑ Surges
❑ Dieseling or run-on

General Information

GM 1-6

AUTOMATIC TRANSMISSION PROBLEMS (if applicable)

PROBLEM OCCURS

❑ Morning ❑ Afternoon ❑ Anytime

ENGINE TEMPERATURE WHEN PROBLEM OCCURS

❑ Cold ❑ Warm ❑ Hot

DRIVING CONDITIONS WHEN PROBLEM OCCURS

DRIVING HABITS

GASOLINE USED

WEATHER CONDITIONS WHEN PROBLEM OCCURS

CHECK ENGINE LIGHT / DASH WARNING LIGHT

❑ Sometimes ON ❑ Always ON ❑ Never ON

PECULIAR SMELLS

STRANGE NOISES

❑ Short - less than 2 miles
❑ 2 ~ 10 miles
❑ Long - more than 10 miles
❑ Stop and go
❑ While turning
❑ While braking
❑ At gear engagement
❑ With A/C operating

❑ With headlights on
❑ During acceleration
❑ Mostly driving downhill
❑ Mostly driving uphill
❑ Mostly driving level
❑ Mostly driving curvy roads
❑ Mostly driving rough roads

❑ Mostly city driving
❑ Highway
❑ Park vehicle inside
❑ Park vehicle outside

❑ Drive less than 10 miles per day
❑ Drive 10 to 50 miles per day
❑ Drive more than 50 miles per day

❑ 87 Octane
❑ 89 Octane

❑ 91 Octane
❑ More than 91 Octane

❑ 32 ~ 55° F (0 ~ 13° C)
❑ Below freezing (32° F / 0° C)

❑ Above 55° F (13° C)

❑ "Hot"
❑ Sulfur ("rotten egg")
❑ Burning rubber

❑ Gasoline
❑ Burning oil
❑ Electrical

❑ Rattle
❑ Knock

❑ Squeak
❑ Other

❑ No symptoms
❑ Shifts too early or too late
❑ Changes gear incorrectly

❑ Vehicle does not move when in

gear

❑ Jerks or bucks

2

2-1 GM

2.1 VEHICLES COVERED

This Code Reader may be used to retrieve engine service codes
from most General Motors (GM) and Saturn domestic cars and
trucks (EXCEPT Geo, Nova, and Sprint). Includes all models
EXCEPT Cadillacs and diesel vehicles. Specific makes and
models are listed below.

Model
Year Make Model

1982-93 Buick Century, Electra, Electra Wagon, Estate

Wagon, Le Sabre, Le Sabre Wagon, Park
Avenue, Reatta*, Regal, Grand National,
Riviera*, Roadmaster, Skyhawk, Skylark,
Somerset

Chevrolet Berreta, Camaro, Caprice, Cavalier, Cele-

brity, Chevette, Citation, Corisca, Corvette,
El Camino, Impala, Lumina, Monte Carlo

Oldsmobile Achieva, Calais, Custom Cruiser, Cutlass

Calais, Ciera, Cutlass Cruiser, Cruiser
Wagon, Cutlass Supreme, Supreme Classic,
Delta 88, Eighty-eight, Firenze, Ninety­eight, Omega, Toronado*, Touring Sedan,
Trofeo*

Pontiac 6000, 6000 STE, Bonneville, Fiero, Firebird,

Grand Am, Grand Prix, J 2000, Lemans,
J Parisienne, Phoenix, Safari, Safari Wagon,

Sunbird, T 1000
Saturn All models
Trucks All one ton capacity or less with gas

and Vans engines

1994 Buick Roadmaster 5.7 liter

Chevrolet Camaro 3.4 liter/5.7 liter, Caprice 5.7 liter,

Caprice 5.7 liter, Cavalier 3.1 liter,

Lumina 3.1 liter
Pontiac Firebird 3.4 liter/5.7 liter, Sunbird 2.0 liter/

3.1 liter
Saturn All models
Trucks All one ton capacity or less with gas

and Vans engines

Retrieving ECM Codes

GM 2-2

* Not applicable to models equipped with climate control

computers

NOTE:

For 1994 and 1995 vehicles, only the models listed
above are compatible with the Code Reader.

The Code Reader

is not compatible with 1996 and

later model year vehicles.

2.1.1 Vehicle Test Connector

GM and Saturn vehicles use one of two types of test
connectors: 12-pin or 16-pin.

12-Pin Connector: The 12-pin
connector was phased out
completely in 1996. Some 1994
and 1995 vehicles still use the
12-pin connector, but because of changes in the ECM, the
Code Reader is not compatible with some of these systems
(see paragraph 2.1).

■ 16-Pin Connector: The new

16-pin connector was introduced
on some 1994 and 1995 models,
and was made standard
equipment on all 1996 and
subsequent model year vehicles.

The Code Reader will
not work on vehicles equipped with the 16-pin
connector.

2.2 BEFORE YOU BEGIN

•

Fix any known mechanical problems before performing
any test.

Make a thorough check before starting any test procedure.
Loose or damaged hoses, wiring, or electrical connectors are
often responsible for poor engine performance, and in some
cases they may cause a “false” fault code.

Model
Year Make Model

1995 Chevrolet Caprice 4.3 liter

Saturn All models
Trucks All one ton capacity or less with gas

and Vans engines (EXCEPT S/T Series vehicles)

1 2 3 4 5 6 7 8
910111213141516

■

2

2-3 GM

Please read your vehicle’s service manual for proper
connection of vacuum hoses, electrical wiring, and wiring
harness connectors. Check the following areas:

a. All fluid levels
b. Air cleaner and ducts
c. Belts
d. Mechanical linkage associated with sensor
e. Vacuum hoses
f. Spark plugs and wires
g. Electrical wiring
h. Electrical connectors
i. Proper battery voltage
j. Fuel system components

2.3 RETRIEVING SERVICE CODES

•

Always observe safety precautions before and during the
testing process.

•

Fix any known mechanical problems before this test.

•

Have pencil and paper handy.

1. Turn off ignition.

2. Connect the Code Reader to the vehicle test connector.

NOTE:

The Code Reader only fits into the connector one way.

3. Set Selector Switch to ECM A-B

position.

4. Turn on ignition. DO NOT

START THE ENGINE.

5. Read codes from the "Check Engine" or "Service Engine

Soon" light (from the "Shift to D2" light - 1991 and 1992
models or the "Temperature" indicator light - 1993 and
subsequent - for Saturn Electronic Transmission codes) on
your vehicle's instrument panel. Be sure to write the codes
down.

NOTE:

If the light does not blink, refer to your vehicle's
service manual for information on checking the
circuitry.

•

All codes are two digits.

Retrieving ECM Codes

GM 2-4

•

Each code is transmitted three times before the next code
is sent.

•

Code sets will begin with Code 12 ("System Pass") even if
fault codes are present.

•

The codes will continue to be sent as long as the ignition is
on and the Code Reader is connected.

•

Count blinks to get the service codes:

•

Code 12 looks like:

NOTE:

Code 12 is not a fault code. Code 12 indicates the
computer's self-diagnostic system is functioning
properly (SYSTEM PASS). If code 12 is the only code
which displays when you perform the diagnostic test,
this means there are no fault codes stored in the
vehicle's computer. Consult your vehicle's repair
manual for "no codes" problems.

•

Code 22 looks like:

IMPORTANT: Any code that ends in zero ("0") is transmitted
as follows:

•

Code 30 looks like:

6. Next, erase service codes (see paragraph 2.4). This will

help you determine which codes are "hard" faults and
which codes are "intermittent" faults.

7. Turn on ignition, start engine, and observe "Service

Engine Soon" light; light should turn off. Run engine for
several minutes (to allow engine to reach normal
operating temperature), then observe "Service Engine
Soon" light:

■ If "Service Engine Soon" light turns on, turn off ignition

and repeat steps 2 through 5. This reveals "hard" fault
codes.

ABNORMALLY LONG PAUSE

BLINK BLINK

= Code 30

BLINK

BLINK

PAUSE

= Code 12

BLINK BLINK

BLINK BLINK

PAUSE

= Code 22

BLINK BLINK

2

2-5 GM

NOTE:

It may be necessary to test drive the vehicle to
reset "hard" fault codes 13, 15, 24, 44, 45, and 55
after they have been erased.

■ If "Service Engine Soon" light does not turn on, the initial

stored fault codes were all "intermittent" fault codes.
(Refer to the "Diagnostic Procedures" section in the
manufacturer's service manual for your vehicle.)

8. Follow the testing and repair procedures outlined in the

manufacturer's service manual for your vehicle to correct
"hard" faults. Codes should be addressed and eliminated
in the order they were received, erasing and retesting
after each repair is made to be sure the fault was
eliminated. Code 12 will appear alone when no other fault
codes are present.

NOTE:

Whenever codes 51, 52, 54, or 55 are displayed with
other codes, troubleshoot and eliminate the "50
Series" codes first, then proceed with the lower­numbered codes.

9. Turn off ignition and remove the Code Reader.

2.3.1 Servicing Fault Codes

Diagnostic trouble codes indicate a problem in a circuit, not
necessarily a faulty component. DO NOT replace components
based only on trouble codes without first following the service
procedures described in your vehicle's repair manual. Most
faults (including those that set trouble codes) are caused by
damaged, shorted or open wiring, damaged or corroded
connections, improper voltages or grounds, or other
mechanical problems.

Sometimes a fault in one circuit or system will cause the
computer to set a fault code for a different circuit or system.

Example:

A defective spark plug wire can cause a "rich condition" fault
code to be set on the oxygen sensor circuit. In this case,
replacing any component in the oxygen sensor circuit will not
correct the fault, because the problem is caused by the
defective spark plug wire and not by the oxygen sensor circuit.
This is called a "false" code.

For this reason, it is

IMPORTANT that you make a thorough
inspection of all systems: wiring, hoses, vacuum, engine
mechanical, charging, ignition, power, ground, fuel, (some of
these systems are not connected to the computer system, but

Retrieving ECM Codes

GM 2-6

will still affect it) before retrieving trouble codes. Refer to your
vehicle's service/repair manual for specifications and system
testing procedures which apply to your particular vehicle.

2.4 ERASING SERVICE CODES

•

Always observe safety precautions before and during
testing process.

1. Turn off ignition.

2. Remove ECM fuse from the fuse block or disconnect the

negative battery cable to disconnect power to the vehicle's
computer.

3. Wait fifteen seconds for codes to be erased from the

computer's memory.

4. Reconnect ECM fuse or reconnect negative battery cable.

NOTE:

Once the computer's memory has been erased your
vehicle may run rough for up to 40 miles while new
information is being saved in the vehicle's computer.
If the battery cable is removed, you will have to
reprogram your radio, clock and memory seat
position.

2.5 ECM SERVICE CODES

•

Consult your vehicle's service manual for detailed
meanings or definitions related to your vehicle.

Refer to the appropriate service codes table for your vehicle:

2.5.1 GM Engine/Electronic Transmission Service Codes;
Saturn Engine Service Codes

2.5.2 Saturn Electronic Transmission Service Codes

Refer to the "Diagnostic Charts" and "Diagnostic Aids" in your
vehicle's service manual to further assist in the fault isolation
and elimination process.

2

2-7 GM

2.5.1 GM Engine/Electronic Transmission Service Codes; Saturn
Engine Service Codes

CODE SERVICE CODE DEFINITION

11 (Saturn vehicles ONLY): Indicates transmission service

codes will be displayed next on the "Shift to D2" light
(1991-92 models) or "Temperature" indicator light (1993
and later models)

12 Diagnostic mode; no distributor signal to Electronic

Control Module; System PASS

13 Oxygen sensor signal fault - signal too low / open left

oxygen sensor circuit (Dual sensor models)

14 Coolant sensor or circuit fault - signal voltage low or

shorted

15 Coolant temperature sensor or circuit fault - signal

voltage high

16 Battery or alternator problem - voltage too high or low

Direct ignition system (DIS) fault line open or shorted to
ground

Ignition system fault - loss of 2X or Low Resolution
Pulse signal

Transmission speed error

17 RPM signal problem

Camshaft sensor - circuit problems
Electronic Control Module (ECM) computer circuit

problem - Pull-up resistor (Saturn)

18 Camshaft or Crankshaft sensor - circuit problems

Fuel Injector circuit is not working properly - possible
blown fuel injector fuse

19 Ignition system fault - Intermittent 7X signal or loss of

58X signal or 6X signal (Saturn)
21 Throttle position sensor (TPS) - signal voltage is high
22 Throttle position sensor (TPS) - signal voltage is low

Fuel cutoff relay circuit - open or shorted to ground
23 Manifold air temperature (MAT) sensor - signal voltage

is low or high

Throttle position sensor (TPS) error

Mixture Control (M/C) solenoid - open or short circuit

problems

Intake Air Temperature Sensor (IAT) low