International VT-275 User Manual

VT 275 V6 ENGINE

model year 2006

FEATURES AND DESCRIPTIONS FOR WORKHORSE CUSTOM CHASSIS APPLICATIONS

FORWARD

This publication is intended to provide technicians and service personnel with an overview of the technical features of the International® VT 275 Diesel Engine. The information contained in this publication is a supplement to information that is contained in available service literature. The photos and illustrations in this publication may vary from your particular vehicle. Consult the latest SERVICE and DIAGNOSTIC manuals for the latest information, before you conduct any service or repairs.

Safety Information

This manual provides general and specic service procedures

and repair methods essential for your safety and the reliable operation of the engine. Since many variations in tools, procedures, and service parts are involved, advice for all of the possible safety conditions and hazards cannot be stated.

Departure from the instructions in this manual or disregard of warnings and cautions can lead to injury, death, or both, and damage to the engine or vehicle.

Read the safety instructions below before doing service and test procedures in this manual for the engine or vehicle. See related application manuals for more information.

Safety Instructions

Vehicle

Make sure the vehicle is in neutral, the parking brake is set, and the wheels are blocked before you perform any work or diagnostic procedures on the engine or vehicle.

Work Area

Keep the work area clean, dry and organized.

•

Keep tools and parts off the oor.

• Make sure the work area is ventilated and well lit.

• Make sure a First Aid Kit is available.

•

Safety Equipment

Fire Prevention

NOTE: Check the classication of each re extinguisher to en-

sure that the following re types can be extinguished:

Type A - Wood, paper, textiles, and rubbish

1. Type B - Flammable liquids

2. Type C - Electrical equipment

Make sure that charged re extinguishers are in the work

• area.

Batteries

Batteries produce highly ammable gas during and after

• charging.

Always disconnect the main negative battery cable rst.

• Always connect the main negative battery cable last.

• Avoid leaning over batteries.

• Protect your eyes.

•

Do not expose batteries to open ames or sparks.

• Do not smoke in workplace.

•

Compressed Air

Limit shop air pressure for blow gun to 207 kPa (30psi).

• Use approved equipment.

• Do not direct air at body or clothing.

• Wear safety glasses or goggles.

• Wear hearing protection.

• Use shielding to protect others in the work area.

•

Use the correct lifting devices.

• Use the proper safety blocks and stands.

•

Protective Measures

Wear protective glasses and safety shoes (do not work in

• bare feet, sandals, or sneakers). Wear the appropriate hearing protection.

• Wear the correct clothing.

• Do not wear rings, watches, or other jewelry.

• Restrain long hair.

•

Tools

Make sure all tools are in good condition.

• Make sure all standard electrical tools are grounded.

• Check for frayed power cords before using power tools.

•

Fluids Under Pressure

Use extreme caution when working on systems under

• pressure. Follow approved procedures only.

•

Fuel

Do not over ll fuel tank. Over ll creates a re hazard.

• Do not smoke in the work area.

• Do not refuel the tank when the engine is running.

•

Removal of Tools, Parts, and Equipment

Reinstall all safety guards, shields and covers after servic-

• ing the engine. Make sure all tools, parts, and service equipment are

• removed from the engine and vehicle after all work is done.

DESIGN FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

OVERVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

COMPONENT LOCATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

ELECTRONIC CONTROL SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

AIR MANAGEMENT SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

FUEL SUPPLY SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

LUBRICATION SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

COOLING SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

SPECIAL TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

HARD START / NO START and PERFORMANACE DIAGNOSTICS . . . . . . . . . . . . . . 53

DIAGNOSTIC TROUBLE CODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

POWER DISTRIBUTION CENTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

ENGINE & CHASSIS SCHEMATIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

GLOSSARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

DIRECT INJECTION TURBOCHARGED DIESEL ENGINE

VT 275 FEATURES

90° V6

• Offset Crankpins

• Rear Gear Train

• Primary Balancer

• Regulated Two-Stage Turbocharging System

• Four Valves per Cylinder

• Cooled Exhaust Gas Recirculation

• Electro-Hydraulic Generation 2 Fuel Injection System

• Top Mounted Oil and Fuel Filters

•

VT 275 0VERVIEW

100

150

200

250

300

350

400

450

500

600

800

1000

1200

1400

1600

1800

2000

2200

2400

2600

2800

3000

3200

3400

3600

100

125

150

175

200

225

250

Torque (ft-lb)

Power (HP)

Engine Speed (RPM)

Load (ft-lb)

Power (HP)

Power & Torque Curve

VT 275 ENGINE SPECIFICATIONS

Engine Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-stroke, direct injection diesel

Conﬁguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V6, pushrod operated four valves / cylinder

Displacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275 cu. in. (4.5 liters)

Bore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.74 in. (95 mm)

Stroke . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.134 in. (105 mm)

Compression Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18.0:1

Aspiration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Twin turbocharged and charge air cooled

Rated Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 hp @ 2700 rpm

Peak Torque . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440 lb-ft @ 1800 rpm

Engine Rotation, Facing the Flywheel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Counterclockwise

Injection System . . . . . . . . . . . . . . . . . . . . . . . . . . Electro-hydraulic generation 2 fuel injection

Cooling Sysytem Capacity (Engine Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 quarts

Lube System Capacity (Engine Only) . . . . . . . . . . . . . . . . . . . . . . . . . . 15 quarts with oil ﬁlter

Horsepower and Torque

The VT 275 engine is offered with only one horsepower and torque rating for the 2005 model year. The engine creates 200 horsepower at 2700 rpm and 440 lb-ft of torque at 1800 rpm. The engine has a high idle speed of 2775 rpm with automatic transmission. The engine idle speed is set at 700 rpm and is not adjustable.

Engine Serial Number

VT 275 ENGINE FAMILY 6NVXH0275AEA

EMISSION CONTROL INFORMATION

ENGINE MANUFACTURED BY:

INTERNATIONAL TRUCK AND ENGINE CORPORATION

1870616C1

INTERNATIONAL

THIS ENGINE HAS A PRIMARY INTENDED SERVICE APPLICATION AS A LIGHT HEAVY-DUTY DIESEL ENGINE AND CONFORMS TO U.S. EPA , CANADIAN, AND AUSTRALIAN ADR-30 2006 MODEL YEAR REGULATIONS. THE ENGINE IS ALSO CERTIFIED FOR SALE IN CALIFORNIA IN NEW VEHICLES RATED ABOVE 14,000 POUNDS GVWR AND IS CERTIFIED TO OPERATE ON DIESEL FUEL. THIS ENGINE IS OBD II EXEMPT.

The Engine Serial Number (ESN) for the VT 275 is located on a machined surface at the left rear corner of the crankcase just below the cylinder head.

The ESN identiﬁes the engine family, the build location, and the sequential build number.

Engine Serial Number Example:

4.5HM2Y0135617

4.5 = Engine displacement H = Diesel, Turbocharged M2 = Motor Truck Y = Huntsville 0135617 = Build Sequence

VT 275 OVERVIEW

Emissions Label

The Environmental Protection Agency (EPA) emissions label is on top of the breather, toward the front, on the left valve cover. The label includes the following:

Advertised horsepower rating

• Engine model code

• Service application

• Emission family and control system

• Year the engine was certiﬁed to meet

• EPA emission standards

Cylinder Numbering

The cylinders on the VT 275 are numbered from the front of the right bank 1, 3, 5 and from the front of the left bank 2, 4 and 6.

The engine ﬁring order is 1-2-5-6-3-4

L Front R

COMPONENT LOCATIONS - FRONT OF ENGINE

HEATER SUPPLY TUBE

FUEL TUBE TO RIGHT BANK

SMOOTH IDLER PULLEY

AIR INLET HEATER

AIR INLET

INTAKE MANIFOLD

MAT SENSOR

BANJO BOLT WITH

CHECK VALVE

POWER STEERING

PUMP BRACKET

BELT TENSIONER

OIL PUMP COVER

COMPONENT LOCATIONS - LEFT FRONT OF ENGINE

GROOVED IDLER PULLEY

BREATHER

SMOOTH IDLER PULLEY

HEATER RETURN TUBE

COOLANT OUTLET

COMPONENT LOCATIONS - LEFT SIDE OF ENGINE

AIR INLET DUCT OIL LEVEL GAUGE

LEFT BANK

GLOW PLUGS

SUPPLY FROM FUEL PUMP

AND PRIMARY FILTER

CMP SENSOR

FUEL RETURN TO TANK

IPR AND

HEAT SHIELD

COMPONENT LOCATIONS - LEFT REAR OF ENGINE

LIFTING EYES

LEFT BANK

EXHAUST MANIFOLD

REAR COVER

COMPONENT LOCATIONS - REAR OF ENGINE

OIL FILTER HOUSING

FUEL FILTER HOUSING

TURBINE HOUSING EXHAUST TUBE ASSEMBLY

HIGH PRESSURE PUMP COVER

COMPONENT LOCATIONS - RIGHT REAR OF ENGINE

HIGH PRESSURE COMPRESSOR HOUSING

COOLANT HEATER

UPPER OIL PAN

LOWER OIL PAN

COMPONENT LOCATIONS - RIGHT SIDE OF ENGINE

OUTLET TO CHARGE AIR COOLER

TURBOCHARGER CROSSOVER TUBE

ICP SENSOR

RIGHT BANK

GLOW PLUGS

CRANKCASE

LOWER

CRANKCASE

CKP SENSOR

COMPONENT LOCATIONS - RIGHT FRONT OF ENGINE

PNEUMATIC ACTUATOR

BOOST CONTROL SOLENOID

HOSE HARNESS

BOOST CONTROL SOLENOID

MAP SENSOR

ECT SENSOR

WATER PUMP

PULLEY

AND FAN DRIVE

COMPONENT LOCATIONS - TOP OF ENGINE WITHOUT HARNESS

HIGH PRESSURE PUMP

HIGH PRESSURE TURBINE HOUSING

EGR VALVE

INJECTOR CONNECTORS

TURBOCHARGER OIL SUPPLY LINE

EOP SWITCH

EOP SENSOR

LOW PRESSURE TURBO COMPRESSOR HOUSING

COMPONENT LOCATIONS - TOP OF ENGINE WITH HARNESS

MAF SENSOR CONNECTOR

(SENSOR NOT SHOWN)

INJECTOR HARNESS CONNECTOR

HARNESS TO CHASSIS-MOUNTED ECM/IDM

BOOST CONTROL SOLENOID

ALTERNATOR FUSIBLE LINKS

(ALTERNATOR NOT SHOWN)

ELECTRONIC CONTROL

ECT

ECM

CKP

IDM

BAP

EOP

MAP

ICPIPR

EGR DRIVE

MODULE

BCS

MAF / IAT

EOT

MAT APS / IVS

CMP

ECL

SYSTEM

ECM and IDM control system

• Dual magnetic pick-up timing sensors

• Electric motor driven EGR valve

• ECM boost control

•

System Features

The VT 275 eng i ne us e s the

• Diamond Logic™ II Control System. The electronic control system features an Engine Control Module (ECM) and an Injector Drive Module (IDM).

The Exhaust Gas Recirculation

• (EGR) valve is positioned by an ECM controlled electric stepper motor. The system uses an EGR drive module to communicate commands from the ECM to the EGR valve.

VT 275 engines use two magnetic

• pickup sensors to determine crankshaft speed and position and camshaft position. Magnetic pick-up sensors feature high reliability and accuracy.

The VT 275 engine uses a twin turbo-

• charger with ECM boost control.

ECM

ELECTRONIC CONTROL SYSTEM

Th e EC M us es sen s or inp u ts to

• control the Injection Pressure Regulator (IPR), the EGR valve, the boost control solenoid, the glow plug relay and the inlet air heater relay. The ECM also shares sensor data with the IDM over communication links between the two modules.

• The IDM is mounted on brackets cast into the ECM. The ECM and IDM are then mounted with vibration isolator grommets to the control module assembly bracket on the Power Distribution Center (PDC).

IDM

The Injector Drive Module (IDM) re-

• ceives sensor information from the ECM over three communication links: the CAN 2 link, the CMPO circuit, and the CKPO circuit. The IDM uses this information to calculate injection timing and duration. The IDM controls injector operation through 48volt signals to the twin injector coils.

INLET AIR HEATER RELAY GLOW PLUG RELAY

CONTROL MODULE

ASSEMBLY BRACKET

ECM

IDM X1

ECM X1

The ECM has four connectors. The

• connectors are called X1 through X4 with ECM X1 being the top ECM connector as mounted on the truck. The IDM has three connectors with IDM X1 being the top connector as mounted on the truck. The ECM X1 and X2 connectors are for engine sensor inputs and X3 and X4 are for chassis inputs. The IDM X1 and X2 connectors are for injector operation and X3 is for chassis inputs and communication between the ECM and IDM.

IDM X2

IDM X3

IDM

ECM X2

ECM X3

ECM X4

EGR DRIVE MODULE

ELECTRONIC CONTROL SYSTEM

EGR Drive Module

The EGR Drive Module receives the desired

• EGR valve position from the ECM over the engine CAN 2 link. The module then sends a series of voltage and ground signals to the Motor U, V, and W terminals of the EGR valve. The voltage signals are Pulse Width Modulated (PWM) to control current ﬂow to the motor ﬁeld coils.

The module receives battery voltage and ground

• through the 12-way engine-to-chassis connector. The module supplies a reference voltage to three position sensors within the EGR valve. The drive module uses the sensor signals to determine the percent of valve opening.

INTAKE MANIFOLD

INLET AIR HEATER

INJECTION PRESSURE REGULATOR (IPR) VALVE SWIVEL CONNECTOR

Inlet Air Heater Element

The Inlet Air Heater element is located in the

• lower side of the intake manifold and projects through the manifold and into the inlet air stream.

The element warms the incoming air to aid

• cold start and reduce emissions during warmup. The ECM turns the inlet air heater on for a predetermined amount of time, based on engine oil temperature, intake air temperature, and barometric air pressure. The inlet air heater can remain on while the engine is running to reduce white smoke during engine warm-up.

Injection Pressure Regulator (IPR) Valve

The IPR mounts to the high-pressure pump

• and controls the amount of oil allowed to drain from the high-pressure system. When the ECM increases the IPR signal duty cycle, the valve blocks the oil’s path to drain and pressure rises. When the ECM reduces the duty cycle, a larger volume of oil is allowed to drain from the system and pressure is reduced. The valve contains a pressure relief valve for the system that opens if system pressure reaches 4500 psi. The IPR is protected by a heat shield that must be reinstalled after servicing.

Inlet Air Heater Relay

The Inlet Air Heater (IAH) element is

• used to improve cold start operation, reduce emissions and white smoke, and improve engine warm-up. The IAH relay is the taller of the two relays. The IAH relay receives battery power from the starter power-feed terminal and the normally open terminal connects to the element through the harness. One end of the relay coil is grounded through the engine 12-way connector. The relay closes when the coil receives voltage from the ECM.

Glow Plug Relay

Glow plugs are used to improve cold

• engine starting. Glow plug operation is controlled by the ECM through the glow plug relay. The relay common terminal is connected by jumper to the common terminal of the Inlet Air Heater relay. The normally open terminal connects to the glow plug harness. One end of the relay coil is grounded through the engine 12-way connector. The relay is closed when the other end of the coil receives voltage from the ECM.

ELECTRONIC CONTROL SYSTEM

AIR HEATER RELAY

GLOW PLUG RELAY

MAF / IAT

5-PIN

CONNECTOR

MASS AIR FLOW (MAF) SENSOR

Mass Air Flow (MAF) Sensor

The Mass Air Flow (MAF) sensor is

• mounted with ductwork between the turbocharger inlet and the air ﬁlter element. The sensor applies voltage to a low resistance thermistor exposed to the fresh air portion of the intake charge. The MAF sensor circuitry measures the increase in voltage required to offset the cooling effect of the air ﬂow over the thermistor. This voltage is then converted into a variable frequency that is sent to the ECM. The MAF value can be read with MasterDiagnostics® software in lb./min.

ELECTRONIC CONTROL SYSTEM

ECM

BATTERY

F-47

TO IDM RELAY

TO ENGINE INLINE 12-WAY

F38

PDC

STARTER MOTOR RELAY

KEY SWITCH

PDC#

F4 F12 F41 F46

Device

30A...IDM/ECM 20A...RU N/ACC 10A...ECM PWR 5A...ECM KEY PWR ECM RELAY - POSITION 50

X1 X2

X3 X4

X1 X2

X3 X4

X3-3 VIGN

X3-5 ECM MPR

X4-1 ECM PWR

X4-2 ECM PWR

ECM Relay Circuit Operation

The ECM controls its own power up

• and power down process. When the key is OFF, the ECM stays powered up for a brief period. The ECM then powers down after internal housekeeping functions have been completed.

Key Power

The Run/Accessory position of the

• Key Switch receives battery voltage from the Power Distribution Center. When the key is ON, the switch supplies battery voltage through fuse F47 to ECM pin X3-3. Battery voltage is available at all times through fuse F38 to ECM relay pins 30 and 86.

Pin 86 supplies voltage to the relay coil.

•

Pin 85 connects the coil to pin X3-5

• of the ECM.

When the key is ON, voltage supplied

• to pin X3-3 signals the ECM that the operator is going to start the engine.

The ECM then supplies a ground circuit to pin X3-5. When this occurs, current ﬂows through the ECM relay coil and creates a magnetic ﬁeld causing the relay to latch. When latched, the relay connects pin 30 to pin 87 and supplies current to the ECM through pin X4-1 and X4-2.

Shut Down

When the key is OFF and voltage is

• removed from ECM pin X3-3, the ECM shuts down the engine but keeps the ECM powered up brieﬂy until the internal house keeping is completed.

ECM Power Relay

ELECTRONIC CONTROL SYSTEM

DTC 112 Electrical system voltage B+ out-of-range high

The ECM detects an alternator output greater than 23 volts at ECM Pin X3-3 for more than 0.5 seconds.

Possible causes: • Voltage increases

• Jump starting the engine

• Incorrect external battery connections

DTC 626 Unexpected reset fault

Set when power is interrupted to the ECM or causes an ECM power down.

Possible causes: • Loose or dirty connections at battery or ground cables

• Power feed wiring problems

• Low battery voltage

DTC 113 Electrical system voltage B+ out-of-range low

The ECM detects less than 7 volts at ECM Pin X3-3 for more than 0.5 seconds.

Possible causes: • Discharged batteries

• Increased resistance in the battery feed circuits

• Failed alternator or ECM power relay

Voltage Checks - ECM Power Relay Socket

Turn Key Switch OFF.

1. Remove ECM relay and inspect for corroded terminals.

2. Connect relay breakout harness to relay and socket.

3. Measure voltage with Key Switch in the required test position.

TEST POINT KEY SWITCH SPECIFICATION COMMENTS

85 to GND ON 0.06 to 2 V If greater than 2 volts, check for open or short to B+.•

85 to GND OFF

for open

86 to GND ON/OFF B+ If no voltage, check the fuse.

30 to GND ON B+ If no voltage, check the fuse.

87 to GND ON B+ If no voltage, check for failed relay.•

87 to GND OFF O V If greater than 0 volts, check for short to B+.•

B+ If no voltage, check the fuse.

• If fuse is good, check for open.

•

• If fuse is blown, check for short to ground.

• If fuse is good, check for open.

•

• If fuse is blown, check for short to ground.

• If fuse is good, check for open.

•

If measurements are OK, send the vehicle to your International® dealer for further diagnostics.

ELECTRONIC CONTROL SYSTEM

BATTERY

F34

F-47

TO IDM RELAY

PDC

F66

STARTER MOTOR RELAY

KEY SWITCH

ENGINE IN-LINE 12-WAY

30 87

86 85

IDM

X3-8 IDM LOGIC POWE R X3-24 IDM MAIN POWER X3-25 IDM MAIN POWE R X3-4 IDM MAIN POWER X3-23 IDM MAIN POWER X3-27 IDM M PR X3-7 VIGN

IDM Relay Circuit Operation

The IDM controls its own power up

• and power down process. When the key is OFF, the IDM stays powered up for a brief period. The IDM then powers down after internal housekeeping functions have been completed.

IDM Power Up

The Key Switch receives battery volt-

• age from the Power Distribution Center (PDC. When the key is ON, the switch supplies battery voltage through F-47 fuse and pin 9 of the engine 12-way connector to pin X3-7 of the IDM.

Battery voltage is available through

• the PDC F-34 fuse to IDM relay pin 30 and 86 at all times. Pin 85 supplies voltage to the relay coil. Pin 85 takes that voltage through pin 8 of the engine 12-way connector to pin X3-27 of the IDM. When the key is ON, voltage supplied to pin X3-7 signals the IDM to provide a ground circuit to pin X3-27. When this occurs, current ﬂow-

ing through the IDM relay coil builds a magnetic ﬁeld that causes the relay to latch. When latched, the relay connects pin 30 to pin 87 and supplies current through pin 12 of the engine in-line 12-way connector to pin X3-4, X3-23, X3-24, and X3-25 of the IDM. Four pins receive voltage to spread the current draw over multiple pins.

IDM Logic

The IDM also requires voltage for the

• internal logic circuit. When the IDM relay latches, pin 87 of the relay supplies voltage to the IDM logic circuit through fuse F-66 in the PDC. The fuse feeds through pin 6 of the engine in-line 12way connector to the IDM pin X3-8.

ELECTRONIC CONTROL SYSTEM

IDM Power Relay

DTC 523 IDM Vign Voltage Low

The ECM detects voltage from VIGN less than 7 volts.

Possible causes: • Connections between the IDM Pin X3-7 and the VIGN

DTC 525 IDM fault

The ECM detects an internal IDM failure.

DTC 533 IDM relay voltage high

The ECM detects voltage from the IDM power relay greater than 16 volts.

Possible causes: • When jump starting the engine

• Incorrect external battery connections

• Alternator voltage output of 16 volts or more

DTC 534 IDM relay voltage low

The ECM detects voltage from the IDM power relay less than 7 volts.

Possible causes: • Discharged batteries

• Increased resistance in the battery feed circuits

• Failed IDM power relay or alternator

Voltage Checks - IDM Power Relay Socket

Turn Key Switch OFF.

1. Remove IDM relay and inspect for corroded terminals.

2. Connect relay breakout harness to relay and socket.

3. Measure voltage with Key Switch in required test position.

TEST POINT KEY SWITCH SPECIFICATION COMMENTS

86 to gnd ON 0.06 to 2 V If greater than 2 volts, check for open or short to B+.•

86 to gnd OFF B+ If no voltage, check the fuse. If fuse is good, check for open.•

85 to gnd ON / OFF B+ If no voltage, check the fuse.

30 to gnd ON B+ If no voltage, check the fuse.

87 to gnd ON B+ If no voltage, check for failed relay.•

87 to gnd OFF 0 V If greater than 0 volts, check for short to B+•

• If fuse is blown, check for short to ground.

• If fuse is good, check for open.

•

• If fuse is blown, check for short to ground.

• If fuse is good, check for open.

•

CONTINUED ON THE NEXT PAGE Ñ

ELECTRONIC CONTROL SYSTEM

IDM Power Relay CONTINUED

Voltage Checks - 12-pin Connector

Turn Key Switch OFF.

1. Remove 12-pin connector.

2. Inspect for bent pins or corrosion.

3. Connect 12-pin breakout harness to chassis harness.

4. Turn Key Switch to the ON position.

TEST POINT SPECIFICATION COMMENTS

9 to gnd B+ If no voltage, check the fuse.

8 to gnd 0.06 to 2 V If greater than 2 volts, check for open.•

12 to gnd B+ If no voltage, check for short to ground or open.•

6 to gnd B+ If no voltage, check fuse.

1 to gnd 0 V If greater than 0 volts, check for open or high resistance (voltage readings indicate

• If fuse is blown, check for short to ground.

• If fuse is good, check for open.

•

• If fuse is blown, check for short to ground.

• If fuse is good, check for open.

•

• poor ground to battery).

Harness Resistance Checks

Turn Key Switch OFF.

1. Remove IDM relay and inspect for corroded terminals.

2. Install relay breakout harness to socket only.

3. Disconnect positive battery cable.

4. Use disconnected positive battery cable for B+ test point.

TEST POINT SPECIFICATION COMMENTS

30 to B+ cable < 5 Ω If greater than 5 Ω, check fuses.

86 to B+ cable < 5 Ω If greater than 5 Ω, check fuses.

• If fuses are good, check for open.

•

• If fuses are good, check for open.

•

ELECTRONIC CONTROL SYSTEM

ECM

BATTERY

200 A

IAH

RELAY

GLOW PLUG RELAY

GPC

GPD

GLOW PLUGS

ECT

STARTER IAH

BAP

X1-17 GPC

X1-21 GPD

2 4 6

1 3 5

12-WAY ENGINE TO CHASSIS CON NECTOR

N.O. TERM INAL

X1 X2

X3 X4

X1 X2

X3 X4

Glow Plug System

The VT 275 uses glow plugs to aid

• cold starts. The ECM turns on the glow plugs prior to engine cranking to increase the temperature of the cylinders. Glow plug operation is controlled by the ECM through the glow plug relay. The glow plugs have full voltage if battery voltage is normal, or pulse width modulated to control the current if battery voltage is above normal. The ECM calculates glow plug ontime based on coolant temperature and barometric pressure. The required time to warm up the cylinders decreases as engine coolant temperature increases. Warm up time decreases as barometric air pressure increases. The glow plugs may continue to be energized after start-up to reduce emissions.

Relay Operation

The glow plug relay receives battery

• voltage to its common terminal from the starter power-feed terminal. The normally open terminal connects to

the individual glow plugs through the glow plug harness. One end of the relay coil is always grounded through pin 4 of the engine 12-way connector. The ECM supplies 12 volts to the other end of the coil through ECM pin X117 in order to close the relay contacts.

Glow Plug Lamp

The glow plug lamp is used as a

• wait-to-start indicator. The ECM lights the glow plug lamp at glow plug activation to signal the operator to wait for the cylinders to warm up.

Both lamp operation and the glow plug

• operation are based on BAP and ECT values but are independent of each other.

The glow plug operation may

• continue after the lamp is off.

Glow Plug Diagnostics

Glow plug diagnostics are used to

• determine if the relay is operating cor-

rectly when commanded on. An additional wire on the relay’s normally open terminal connects to ECM pin X1-21. This circuit, GPD, allows the ECM to monitor the relay operation.

The glow plugs can be turned on using

• the KOEO Glow Plug/Inlet Air Heater Test. The test can only be activated twice per key cycle.

GPC (Glow Plug Control) Circuit

ELECTRONIC CONTROL SYSTEM

DTC 251 Glow Plug Control OCC self-test failed

Key On Engine Off Standard Test detects a fault in the glow plug relay control circuit.

Possible causes: • Open or short in GPC signal circuit

• Open in actuator power ground

• Open glow plug relay coil

DTC 375 Glow Plug Relay Circuit Fault

The ECM does not see the expected relay output voltage value.

Possible causes: • Open in the B+ supply circuit to glow plug relay

• Open or short in GPC circuit

• Failed glow plug relay

Note: If DTC 251 and DTC 375 are both set, repair DTC 251

Voltage Checks - Relay

ﬁrst.

Measure voltage with Key Switch in the required test position (on-time is temperature dependent).

TEST POINT KEY SWITCH SPECIFICATION COMMENTS

GP relay control terminal to GND

Actuator Pwr

Gnd to gnd

GP battery sup-

ply terminal to

gnd

GP relay output

terminal to gnd

GP relay output

terminal to gnd

ON B+ If no voltage, check for short to ground or open.•

OFF 0 V If greater than 0 V, check for short to power.•

OFF 0 V If greater than 0 V, check for open.•

ON B+ If no voltage, check the fuse.

ON B+ If no voltage, check for failed relay.•

OFF 0 V If greater than 0 volts, check for short to B+ or check for failed

• If fuse is blown, check for short to ground.

• If fuse is good, check for open

•

• relay

ELECTRONIC CONTROL SYSTEM

ECM

BATTERY

200 A

IAHC

IAHD

MAF / IAT

IAH

RELAY

EOT

STARTER IAH

BAP

X1-18 IAHC

X2-11 IAHD

N.O. TERM INAL

12-WAY ENGINE TO CHASSIS CON NECTOR

X1 X2

X3 X4

X1 X2

X3 X4

Inlet Air Heater Operation

The VT 275 has an Inlet Air Heater

• (IAH) element mounted in the front of the intake manifold. The IAH is used to improve cold start operation, reduce emissions and white smoke, and improve engine warm-up. When the key is ON, the ECM determines if the element should be activated and for how long, based on barometric pressure and engine oil temperature. On time is limited to prevent heater element damage and to prevent damage to the intake manifold. The heater relay delivers full voltage to the element if battery voltage is normal, or the relay is pulsed by the ECM to control the current if battery voltage is above normal. If the battery voltage is so low that the starter motor operation may be affected, the inlet air heater is disabled.

Relay Operation

The IAH relay receives battery power

• from the starter power feed terminal. The normally open terminal connects

to the element through the harness. One end of the relay coil is always grounded through pin 4 of the engine 12-way connector. The other end of the coil receives 12 volts from ECM pin X1-18 to close the relay contacts.

Inlet Air Heater Diagnostics

An additional wire on the normally

• open terminal connects to ECM pin X2-11. This diagnostic circuit allows the ECM to determine if the IAH relay is on when commanded on by the ECM.

The Inlet Air Heater can be turned on

• using the KOEO Glow Plug/Inlet Air Heater Test. The test can only be activated twice per key cycle. The ECM will delay the Inlet Air Heater operation for three seconds after the test is activated.

IAH (Inlet Air Heater) Circuit

ELECTRONIC CONTROL SYSTEM

DTC 238 Inlet Air Heater Control OCC self-test failed

Key On Engine Off Standard test detects a fault in the inlet air heater control circuit.

Possible causes: • Open or short in IAHC circuit

• Open in actuator power ground

• Open inlet in air heater relay coil

DTC 373 Inlet Air Heater relay circuit fault

The ECM does not see the expected relay output voltage value.

Possible causes: • Open in the B+ supply circuit to inlet air heater relay

• Open or short in IAH control circuit

• Failed inlet air heater relay

Note: If DTC 238 and DTC 373 are both set, repair DTC 238

Voltage Checks - Relay

ﬁrst.

Measure voltage with Key Switch in the required test position (on-time is temperature dependent).

TEST POINT KEY SWITCH SPECIFICATION COMMENTS

IAH relay control

terminal to gnd

IAH relay control

terminal to gnd

Actuator Pwr

Gnd to gnd

IAH battery sup-

ply terminal to

gnd

IAH relay output

terminal to gnd

IAH relay output

terminal to gnd

ON B+ If no voltage, check for short to ground or open.•

OFF 0 V If greater than 0 V, check for short to power.•

ON 0 V If greater than 0 V, check for open.•

ON B+ If no voltage, check the fuse.

ON B+ If no voltage, check for failed relay.•

OFF 0 V If greater than 0 volts, check for short to B+ or check for failed

• If fuse is blown, check for short to ground.

• If fuse is good, check for open

•

• relay

ELECTRONIC CONTROL SYSTEM

IDM

ECM

E D C B A

MAF / IAT

EGR DRIVE MODULE

BCS

IPR

EGR

VALVE

RIGHT BANK INJECTORS

X1-7 IAT

X1-6 IAT SIG GRD

X2-2 MAF

LEFT BANK INJECTORS

FIXED RESISTOR

HEATED ELEM ENT

FIXED

RESISTOR

THER MISTO R

MAF

ECM

VREF

SIG

GRD

MICROPROC ESSOR

ENGINE IN-LINE 12-WAY CON NECTOR

ACT GRD

KEY PWR

MAF SIGNAL

KEY POWER

ACTUATOR GR D

SIGNAL GRD

IAT

B+

SIGNAL CONTROL

Mass Air Flow (MAF) Sensor

The MAF sensor is used to measure

• the mass of the fresh air portion of the intake air charge. To reduce Oxides of Nitrogen (NOx), a portion of the fresh air charge is displaced with cooled exhaust gases. The ECM calculates the total engine gas ﬂow based on MAT, MAP and RPM. The ECM then determines the required EGR percent based on the current engine operating conditions. At this point, the ECM commands the exhaust portion of the total charge through the EGR valve while monitoring the fresh air portion through the MAF sensor.

Sensor Construction

The sensor housing contains two

• sensors, the MAF sensor and the Intake Air Temperature (IAT) sensor. The MAF sensor contains a heated element placed in the air stream. The amount of electrical power needed to maintain the element at the proper temperature depends directly on the

mass of air moving over the element.

Sensor Operation

The MAF sensor is made up of two

• voltage divider circuits. A thermistor and a ﬁxed resistor make up one voltage divider circuit, and the heated element and a ﬁxed resistor make up the other voltage divider circuit. The two voltage divider circuits are combined into a bridge circuit with a common power supply and a common ground.

During operation, when voltage is ap-

• plied to the bridge, the temperature of the heated element increases and the resistance decreases. This affects the output of the divider circuit.

The thermistor side is affected only

• by ambient air temperature. The divider voltages are compared and the input voltage to the bridge is increased or decreased until both divider voltages are equal.

An increase or decrease in air-

• ﬂow will change the ratio between the divider voltages, which results in a change to the supply voltage.

The signal controller circuit measures

• the voltage to the bridge and, based on that value, sends a frequency signal to the ECM.

MAF (Mass Air Flow) Sensor

ELECTRONIC CONTROL SYSTEM

DTC 148 MAF signal frequency out of range low

The ECM detects MAF frequency less than 200 Hz for 5 seconds.

Possible causes: • Open or short to ground in the MAF signal circuit

• Open in VIGN circuit

• Open in ground circuit

• Failed MAF sensor

DTC 149 MAF signal frequency out of range high

The ECM detects MAF frequency more than 11,500 Hz for 5 seconds.

Possible causes: • Short to voltage in the MAF signal circuit

• Failed MAF sensor

Voltage Checks - 12-Pin Connector

DTC 166 Mass air ﬂow sensor in-range fault

The ECM detects MAF reading is above 20 gps at key-on-engine-off, MAF is not reading 15 +/- 5 gps at low idle (in Park or Neutral), or MAF is not reading 25 +/- 5 gps at low idle (in Drive).

Possible causes: • Biased MAF/IAT sensor

• Plugged or leaking air intake or air ﬁlter

• Plugged exhaust system

DTC 167 Excessive mass air ﬂow

The ECM detects MAF readings above a calibrated set point based on engine rpm. MAF signal will be restricted to 300 gps.

Possible causes: • Biased or disconnected MAF/IAT sensor

• Short to voltage in the MAF signal circuit

Turn Key Switch to OFF.

1. Disconnect the 12-Pin connector.

2. Inspect for bent pins or corrosion.

3. Connect 12-pin breakout harness.

4. Disconnect negative battery cable. Use negative battery cable as the ground test point.

5. Turn Key Switch to the ON position.

TEST POINT SPECIFICATION COMMENTS

Pin 4 (12pin) to

gnd

Pin 9 (12pin) to

gnd

0 V If greater than 0 volts, check for open.•

B+ If less than B+, check for short to ground or open.•

ELECTRONIC CONTROL SYSTEM

ECM

BATTERY

F40

F65

HFCM

PDC

FUEL PUMP RELAY

RUN / ACC

RELAY

X3-9 FPC

X4-15 FPM

X3-1 WIF

GRD

PUMP

HEATER

86 87

X1 X2

X3 X4

X1 X2

X3 X4

PDC#

F11

F19

Device

20A...FUEL PUMP 20A...FUEL HEATER

KEY SWITCH

F28

Pump Operation

The VT 275 has an ECM controlled

• chassis mounted electric fuel pump. At key-on, the ECM will operate the fuel pump for up to 60 seconds to prime the system. Priming allows the pump to pressurize the system and to allow air in the system to bleed out through an oriﬁce between the ﬁlter housing and the fuel return circuit. When the engine is in run mode, the pump will operate continuously. If the engine dies or is shut down, or if it is not started within 60 seconds, the ECM will stop the pump.

Circuit Operation

To operate the pump, the ECM provides

• a ground at ECM pin X3-9 to latch the fuel pump relay. The relay takes power from fuse F40 and provides it to pin 1 of the pump connector. The ECM monitors the relay’s operation through ECM pin X4-15. Battery voltage should be present at X4-15 when the relay is commanded on. If the ECM does not detect the voltage, a DTC will be logged.

Fuel Heater

The Horizontal Fuel Conditioning Mod-

• ule (HFCM) contains a fuel heater. When the key is ON, the key switch provides power to pin 1 of the heater connector through fuse 65. The heater element contains a thermostat that controls the heater operation.

Water-In-Fuel Sensor

The pump module contains a Water-

• In-Fuel (WIF) sensor. The WIF sensor receives voltage from fuse 65. If the ﬁlter detects water, the sensor sends the voltage to ECM pin X3-1. The ECM then activates the dash WIF lamp.

Engine Coolant Level The Engine Coolant Level (ECL) sen-

• sor uses a ﬂoating ball and a magnetic switch. When the coolant level is full, the ﬂoat will rise and the magnet will pull the ECL contacts open. When the level falls, the contacts close.

ECM Pin X3-4 supplies a 5v signal to

• pin A of the ECL sensor. Pin B of the sensor connector is grounded through the chassis harness. When the level is OK, the switch is open and the ECM will see ﬁve volts on the circuit. If the level is low, the switch is closed and the circuit is grounded. With the circuit grounded the voltage goes to zero.

The ECM can not detect an open or

• short circuit in the ECL system but does continuously monitors the circuit for in-range faults. When the ECM detects a voltage between 3.4 and 4.3 it is assumed there is a circuit failure and an in-range fault, DTC 236 will be set. This failure can be caused by a high resistance connection or an intermittent short to ground.

ELECTRONIC CONTROL SYSTEM

HFCM (Horizontal Fuel Conditioning Module) Fuel Pump

DTC 237 Fuel Pump Control OCC self-test failed

Key On Engine Off Standard Test detects a fault in the fuel pump relay control circuit.

Possible causes: • Open or short to ground on FPC circuit

• Open or short to ground on VIGN circuit to the fuel pump relay

• Open fuel pump relay coil

DTC 374 Fuel Pump Relay Circuit failed

The ECM does not see the expected relay output voltage value.

Possible causes: • Open in the B+ supply circuit to fuel pump relay

• Open or shorted FPC circuit

• Failed fuel pump relay Note: If DTC 237 and DTC 374 are both set, repair DTC 237 ﬁrst.

Voltage Checks - Relay

Turn Key Switch OFF.

1. Remove fuel pump relay and inspect for corrosion.

2. Connect relay breakout harness to relay and socket.

3. Measure voltage with Key Switch in the required test position (pump on-time is 60 seconds).

TEST POINT KEY SWITCH SPECIFICATION COMMENTS

85 to gnd ON 0 to 0.25 V If greater than 0.25 volts, check for open or short to B+.•

85 to gnd OFF 0 V If greater than 0 volts, check for short to B+.•

86 to gnd ON B+ If no voltage, check the fuse.

30 to gnd ON B+ If no voltage, check the fuse.

87 to gnd ON B+ If no voltage, check for failed relay.•

87 to gnd OFF 0 V If greater than 0 volts, check for short to B+•

• If fuse is blown, check for short to ground.

• If fuse is good, check for open.

•

• If fuse is blown, check for short to ground.

• If fuse is good, check for open

•

Harness Resistance Checks - Relay to Ground

Turn Key Switch to OFF.

1. Remove fuel pump relay and inspect for corrosion.

2. Connect relay breakout harness to the socket only.

3. Disconnect negative battery cable. Use disconnected negative battery cable for ground test point.

TEST POINT SPECIFICATION COMMENTS

85 to gnd > 1 kΩ If less than 1 kΩ, check for short to ground.•

86 to gnd > 1 kΩ If less than 1 kΩ, check for blown fuse or short to ground.

30 to gnd > 1 kΩ If less than 1 kΩ, check for blown fuse or short to ground.•

87 to gnd > 1 kΩ If less than 1 kΩ, check for blown fuse or short to ground.•

•

Note: If Key Switch is grounded when Key Switch OFF this will be less than 5 Ω.

•

CONTINUED ON THE NEXT PAGE Ñ

ELECTRONIC CONTROL SYSTEM

HFCM (Horizontal Fuel Conditioning Module) Fuel Pump CONTINUED

Harness Resistance Checks - Relay to VIGN

Turn Key Switch to OFF.

1. Remove fuel pump relay and inspect for corrosion.

2. Connect relay breakout harness to the socket only.

3. Disconnect negative battery cable. Use disconnected negative battery cable for ground test point.

TEST POINT SPECIFICATION COMMENTS

86 to VIGN < 5 Ω If greater than 5 Ω, check VIGN and fuses, if OK check for open.•

Harness Resistance Checks - Relay to Pump

Turn Key Switch to OFF.

1. Disconnect fuel pump connector.

2. Inspect for bent pins or corrosion.

3. Remove fuel pump relay and connect relay breakout harness to socket only.

TEST POINT SPECIFICATION COMMENTS

87 to Pin 1 < 5 Ω If greater than 5 Ω, check for open.•

Harness Resistance Checks - Fuel Pump Connector to Ground

Turn Key Switch to OFF.

1. Disconnect fuel pump connector.

2. Inspect for bent pins or corrosion.

3. Disconnect negative battery cable. Use disconnected negative battery cable for ground test point.

TEST POINT SPECIFICATION COMMENTS

Pin 1 to gnd > 1 kΩ If less than 1 kΩ, check for short to ground.•

Pin 2 to gnd < 5 Ω If greater than 5 Ω, check for open.•

ELECTRONIC CONTROL SYSTEM

ECM

APS / IVS

IN CAB C RUI SE SWITCHES

TO RELAY 10

(RUN / CRANK)

BAP

IDM

EGR DRIVE MODULE

BCS

IPR

EGR

VALVE

RIGHT BANK INJECTORS

LEFT BANK INJECTORS

PDC

X4-6 COO

X3-14 RAS

X3-21 SCS

X3-24 BAP

X4-18 APS

X4-24 GRD

X4-4 VREF B

X4-12 IVS

X1 X2

X3 X4

X1 X2

X3 X4

PDC#

F46

Device

5A...ECM KEY PWR

F58

F45

B+

Accelerator Pedal Position Sensor /

Idle Validation Switch (APS/IVS)

The APS/IVS sensor has two compo-

• nents built into one housing: the Accelerator Pedal Position Sensor (APS) and the Idle Validation Switch (IVS).

The APS is a potentiometer type sen-

• sor. The ECM supplies a reference voltage (Vref) and ground to the potentiometer and the sensor sends a voltage signal back to the ECM indicating the pedal position. The idle validation switch receives 12 volts from the chassis harness and signals the ECM when the pedal is in the idle position. If the ECM detects an APS signal out of range high or low, the ECM will ignore the APS signal and operate at low idle.

If a disagreement in the state of IVS

• and APS is detected by the ECM, and the ECM determines that the IVS is at fault, the ECM will allow a maximum of 50% of APS. If the ECM cannot de-

termine that the IVS is at fault, the engine will be restricted to low idle only.

Barometric Absolute Pressure (BAP) sensor

The BAP sensor is mounted in the cab.

• The BAP sensor provides altitude information to the ECM, so fuel quantity and timing, glow plug on time, intake heater on time, and the operation of the Boost Control Solenoid can be adjusted to compensate for air density changes.

Cruise Control

Cruise control operation is controlled

• through the ECM. Two switches in the cab are used to signal the operator’s intention for speed control. The Cruise On/Off (COO) switch sends a voltage signal to ECM pin X4-6. With the COO switch on, the operator can use the Set (SCS) and resume (RES) switch to control the vehicle speed.

ELECTRONIC CONTROL SYSTEM

Accelerator Pedal Position / Idle Validation Switch (APS/IVS)

DTC 131 APS Out of Range Low

The ECM detects less than 0.147 volts on the APS signal circuit. Engine rpm restricted to idle.

Possible causes: • Short to ground or open in APS signal circuit

• Short to ground or an open in VREF circuit

DTC 132 APS Out of Range High

The ECM detects greater than 4.55 volts on the APS signal circuit. Engine rpm restricted to idle.

Possible causes: • Short to VREF or B+ in APS signal circuit

• short to ground or an open in VREF circuit

Voltage Checks - Connector

Turn Key Switch to OFF.

1. Disconnect harness from sensor.

2. Inspect for bent pins or corrosion.

3. Connect breakout harness to chassis harness only.

4. Turn Key Switch to ON.

DTC 133 APS Signal In-Range

The APS and IVS signals disagree, APS signal is at fault. Engine rpm will be restricted to idle.

DTC 134 APS and IVS signals disagree

The APS and IVS signals disagree, both signals are at fault. Engine rpm will be restricted to idle.

DTC 135 IVS Circuit Fault

The APS and IVS signals disagree, IVS is at fault. In this case the ECM limits the APS signal to 50% maximum.

TEST POINT SPECIFICATION COMMENTS

E to gnd 0 to 0.25 V If greater than 0.25 volts, check for short to VREF or B+.•

K to gnd 0 V If greater than 0 volts, check for short to VREF or B+.•

D to gnd 5 ± 0.5 V If greater than spec, check for short to B+. If less than spec, check for open or short

G to gnd 0 to 0.25 V If greater than 0.25 volts, check for short to VREF or B+.•

J to gnd B+ If less than 10.5 volts, check for blown fuse, open, or high resistance.•

• to ground.

Resistance Checks – Connector to Chassis Ground

Turn Key Switch to OFF.

1. Disconnect harness from sensor.

2. Inspect for bent pins or corrosion.

3. Disconnect negative battery cable. Use disconnected negative battery cable for ground test point.

TEST POINT SPECIFICATION COMMENTS

E to gnd > 1 kΩ If less than 1 kΩ, check for short to ground.•

K to gnd < 5 Ω If greater than 5 Ω, check for open.•

D to gnd > 500 Ω If less than 500 Ω, check for short to ground.•

G to gnd > 1 kΩ If less than 1 kΩ, check for short to ground.•

J to gnd > 1 kΩ If less than 1 kΩ with fuse removed, check for short to ground.•

ELECTRONIC CONTROL SYSTEM

IDM

ECM

2 3

ENGINE IN-LINE

12-WAY CONNECTOR

9-WAY DIAGNOSTIC

CON NECTOR

X3-28 X3-29

X3-12 CAN 1 (+)

X3-13 CAN 1 (-)

X4-20 ATA (+)

X4-21 ATA (-)

X3-4 ECL

COOLANT LEVEL SENSOR

B A

ENG INE HA RNES S

SPLIC E 84 RIN G TERM INAL

(SEE WO RKHO RSE CH ASSIS MANUAL

FOR TER MINATION POI NT

ON EN GIN E / CHASS IS)

TO TRANS CONTRO LLER

Engine/Chassis Communications

The ECM and IDM communicate over

• three independent communication links. The three links are CMPO, CKPO, and CAN 2. In addition to communications with the IDM, the ECM also sends engine information over the CAN 1 link to the vehicle’s instrument cluster and the 9-pin Diagnostic connector.

Cam Position Output (CMPO)

The CMPO signal is a 0-12V digital sig-

• nal used to communicate the camshaft position to the IDM. The CMPO signal is a square wave signal derived from the information contained in the camshaft position sensor’s AC voltage signal. The ECM generates the CMPO signal by pulling down (switching to ground) a single wire 12V circuit that originates in the IDM. The IDM reads the signal and uses it for injector timing calculations.

Crank Position Output (CKPO)

The CKPO signal is a 0-12V digital sig-

• nal used to communicate the crankshaft

position and speed to the IDM. The CKPO signal is a square wave signal derived from the information contained in the crankshaft position sensor’s AC voltage signal. The ECM generates the CKPO signal by pulling down (switching to ground) a single wire 12V circuit that originates in the IDM. CKPO is used by the IDM for injector timing and fuel quantity calculations.

American Trucking Association (ATA) Datalink

The ATA link is a 0-5V signal that enables

• communications between the ECM and the Master-Diagnostics software. The data communication link also allows for programming of the ECM and IDM.

Engine Coolant Level The Engine Coolant Level (ECL) sen-

• sor uses a ﬂoating ball and a magnetic switch. When the coolant level is full, the ﬂoat will rise and the magnet will

pull the ECL contacts open. When the level falls, the contacts close.

ECM Pin X3-4 supplies a 5v signal to

The ECM can not detect an open or

ECM/IDM Communications

ELECTRONIC CONTROL SYSTEM

DTC 231 ATA data communication link error

The ECM can not access the ATA datalink. DTCs can only be retrieved using the cruise control feature.

Possible causes: • Failed ATA device pulling signal to ground

• Open or shorted ATA+ or ATA-

• Exceeded limit on number of ATA devices

• Failed ECM

DTC 236 ECL switch circuit fault

The ECM detects a voltage between 3.4 and 4.3 volts at ECM Pin X3-4 for more than 2.0 seconds.

Possible causes: • High resistance connection

• Intermittent short to ground

ATA Connector Diagnostics Voltage Checks

Turn Key Switch to ON (the engine shoud not be started).

TEST POINT SPECIFICATION COMMENTS

B to A B+ If no voltage, check for open or short on ground and power circuits.•

ATA Connnector Diagnostics Harness Resistance Checks

Turn Key Switch to OFF.

1. Disconnect negative battery cable. Use disconnected battery cable for ground test point.

TEST POINT SPECIFICATION COMMENTS

B to fuse < 5 Ω If greater than 5 Ω, check for open or short to ground.•

A to gnd < 5 Ω If greater than 5 Ω, check for an open.•

Coolant Level Sensor Connector

Turn Key Switch to OFF.

1. Disconnect ECL sensor from harness. Inspect for bent pins or corrosion.

2. Check for FULL coolant level in surge tank.

3. Turn Key-Switch to ON.

TEST POINT SPECIFICATION COMMENTS

A to gnd 5 ± 0.5 V If less than 5 volts, check for open, short to ground, or failed ECM.•

B to gnd 0 V If greater than 0 volts, check for short to power.•

Resistance Checks - Coolant Level Sensor

Disconnect ECL sensor connector and measure across sensor pins.

TEST POINT SPECIFICATION COMMENTS

A to B > 1 k Ω If less than 1 k Ω, check for low coolant in surge tank or failed sensor.•

Harness Resistance Checks - Coolant Level Sensor

Turn Key-Switch to OFF.

1. Disconnect ECL sensor from harness. Inspect for bent pins or corrosion.

2. Disconnect negative battery cable. Use disconnected battery cable for ground test point.

TEST POINT SPECIFICATION COMMENTS

B to gnd < 5 Ω If greater than 5 Ω, check for open.•

ELECTRONIC CONTROL SYSTEM

ECM

F45

PDC

HPSW LPSW

X3-10 AC DEMAND

X3-22 AC CONTR OL

SEE BODY BUILDE R

TO BATTERY POSITIVE

NC NO

C A

BATTERY GRD

A/C

CLUTCH

A/C CLUTCH

DIODE

A/C CLUTCH

RELAY

A/C Clutch Control

The VT 275 ECM controls the

• A/C clutch. The ECM receives an A/C demand signal from the chassis, and engages the A/C clutch.

A/C Demand

The A/C demand signal originates

• at the ECM as a reference voltage on X3-10. The ECM supplies 5 volts to pin 10 and considers clutch engagement when the voltage is pulled low (shorted to ground) by the A/C on/off switch in the dash located A/C Control Head. The low-pressure switch (LPSW), high-pressure switch (HPSW), and the thermostat switch (T-STAT SW) are in series in the A/C demand circuit. If the compressor head pressure rises above 430 psi, the high-pressure switch opens and the demand signal will be 5V. If pressure on the low side of the compressor goes below 7 psi, the low-pressure switch will open and the demand signal will be 5V. The last switch is the

•

thermostat control in the A/C Control Head. If the thermostat is positioned so that in-cab temperature demands are satisﬁed, the thermostat will open and the demand signal will be 5V.

A/C Control

If the A/C demand signal is pulled low, the ECM pulls the AC Control circuit low at pin X3-22. When pin 22 is low, a ground is provided for the A/C Clutch Relay. The relay latches and battery voltage is provided to the A/C clutch through pin 5 of the engine 12-way connector.

Switches

The thermostatic switch (T-STAT SW) monitors evaporator core temperature to prevent freezing and to regulate cab temperatures.

The low pressure switch (LPSW) prevents compressor damage in the event of a refrigerant leak.

The high pressure cutoff Switch (HPSW) interrupts compressor operation in the event of high system pressures.

ELECTRONIC CONTROL SYSTEM

A/C Clutch Control

DTC 268 A/C Clutch Control OCC self-test failed

Key Switch ON, engine OFF. The standard test detects a fault in the A/C/ Clutch Control circuit.

Possible causes: • Open or short to ground on A/C control circuit

• Open or short to ground on power circuit to the A/C clutch relay

• Open A/C clutch relay coil circuit

Voltage Checks - Relay (A/C Switch OFF)

Turn Key Switch to OFF.

Remove A/C clutch relay and inspect for corrosion.

Connect relay breakout harness to to relay and socket.

Measure voltage with the Key Switch in the required test position.

TEST POINT KEY SWITCH SPECIFICATION COMMENTS

85 to gnd ON / OFF B+ If no voltage, check the fuse. If fuse is blown, check for short to

30 to gnd ON / OFF B+ If no voltage, check for short to ground or open.•

86 to gnd ON / OFF B+ If no voltage, check for failed relay.•

87 to gnd ON / OFF 0 V If greater than 0 volts, check for short to B+ or failed relay.•

• ground. If fuse is good, check for open.

Voltage Checks - Relay (A/C Switch ON)

Turn Key Switch to OFF.

1. Remove A/C clutch relay and inspect for corrosion.

2. Connect relay breakout harness to to relay and socket.

3. Measure voltage with the Key Switch ON.

4. A/C system must be charged to speciﬁcations with the engine running and the A/C demand switch ON. (A/C Demand

5. Signal at ECM X3-10 must be set low during these tests.)

TEST POINT KEY SWITCH SPECIFICATION COMMENTS

86 to gnd ON 0 to 0.25 V If greater than 0.25 volts, check for open or short to B+.•

87 to gnd ON B+ If no voltage, check for failed relay.•

Voltage Checks - 12-pin Connector

Turn Key Switch to OFF.

1. Remove the 12-pin connector.

2. Inspect for bent pins or corrosion.

3. Connect 12-pin breakout harness to chassis harness.

4. Disconnect the A/C clutch connector.

5. Turn Key Switch ON.

6. A/C system must be charged to speciﬁcations with the engine running and the A/C demand switch ON.

TEST POINT SPECIFICATION COMMENTS

5 to gnd B+ If no voltage, check for short to ground or open.•

7 to gnd 0 to 0.25 V If greater than 0.25 volts, check for open or short to B+.•

AIR MANAGEMENT

Inlet air

Compressed air

Exhaust gas

Crankcase vapors

Charge Air Cooler

(CAC)

Air filter

MAF/IAT

sensor

Dual stage

turbocharger

Normal exhaust

flow bypass

shut

Exhaust flow bypass open

Right

exhaust in

Left

exhaust in

IAH

MAP

Right cylinder

head

Right exhaust

manifold

Exhaust system

Left cylinder

head

Left exhaust

manifold

MAT

EGR valve

Intake

manifold

EGR

cooler

Exhaust tube assembly

Exhaust to dual stage

turbocharger

Left Right

SYSTEM

Regulated two-stage turbocharger

• Cooled exhaust gas recirculation

• Intake air heater

•

System Features

The Air Management System consists of the air

• ﬁlter, two-stage turbocharger, charge air cooler, intake manifold, Exhaust Gas Recirculation (EGR) cooler and EGR valve. The mass air ﬂow sensor, the intake air temperature sensor, the manifold air temperature sensor, the manifold absolute pressure sensor, and the EGR valve position sensors within the EGR valve are all inputs from the system to the ECM. The ECM controls the system through the EGR valve, and the turbocharger boost control solenoid.

System Operation

The VT 275 uses a regulated two-stage tur-

• bocharger to boost the volume of air ﬂowing into the cylinders. The system consists of two turbochargers with exhaust ﬂow through the units controlled by the turbocharger boost control solenoid. The smaller of the two turbochargers is identiﬁed as the high-pressure turbocharger and is sized to provide boost for low to medium speeds. The larger turbo-

charger is the low-pressure turbo and is sized to work in tandem with the high-pressure unit to provide the boost and air ﬂow needed for highspeed, high-load engine conditions.

Air passes through the air ﬁlter ele-

• ment and the mass air ﬂow sensor to enter the compressor of the lowpressure turbocharger. Air that leaves the low-pressure compressor ﬂows through the crossover tube to the compressor inlet of the high-pressure turbocharger. Air from the compressor goes to the Charge Air Cooler (CAC).

The CAC is mounted in front of the ra-

• diator. The cooler is an air-to-air heat exchanger that uses airﬂow to remove heat energy from the pressurized intake charge. Reducing the temperature of the air increases the charge density, which results in a more efﬁcient engine with quicker engine response and reduced emissions.

After the CAC, the air ﬂows through

• piping to the intake manifold where it is distributed to the cylinders.

Exhaust ﬂow from the cylinders exits

• the exhaust manifolds and spools up the high-pressure turbine. The exhaust passes through the high-pressure turbine and enters the low-pressure turbine. The exhaust gases then exit the turbine and ﬂow out the exhaust system.

A bypass valve controls the exhaust

• ﬂow through a passage that allows a portion of the exhaust to bypass the high-pressure turbine and go directly to the low-pressure turbine. Part of the exhaust gas that leaves the left bank exhaust manifold is diverted to the EGR cooler. Heat energy is removed from the exhaust while in the cooler and transferred to the engine’s coolant. The cooled exhaust gases then ﬂow through a short internal passage in the intake manifold to the EGR valve. The EGR valve meters a portion of the cooled exhaust gases into the intake manifold where the exhaust displaces a portion of the fresh air charge.

AIR MANAGEMENT SYSTEM

FROM CHARGE AIR COOLER (CAC)

LOW PRESSURE COMPRESSOR INLET

INTAKE MANIFOLD

LOW PRESSURE

TURBINE OUTLET

EXHAUST TUBE ASSEMBLY

Air Filter Restriction Gauge

The ﬁlter restriction gauge is mounted

• on the air ﬁlter housing. The gauge allows the operator to check the condition without removing the ﬁlter. The restriction gauge can be reset by pushing the yellow button on the end.

Note: The ﬁlter restriction gauge bel-

•

lows will lock in position if restriction exceeds 26 inches of water. The ﬁlter should be replaced and the gauge reset.

The ﬁlter element should be replaced if

• restriction passes 12.5 inches of H2O when tested at high-idle, no-load with a magnehelic gauge.

EGR VALVE

BOOST CONTROL SOLENOID

PNEUMATIC ACTUATOR

COMPRESSOR OUTLET TO

CHARGE AIR COOLER (CAC)

AIR FILTER RESTRICTION GAUGE

FUEL SUPPLY

SYSTEM

Chassis-mounted electric fuel pump

• Water-in-fuel detection

• Electric fuel heater

• Chassis-mounted primary fuel ﬁlter

• Engine-mounted secondary fuel ﬁlter element

•

BANJO BOLT

FILTER INLET

SECONDARY FUEL FILTER HOUSING

System Features

The VT 275 uses a chassis-mount-

• ed electric fuel pump. The pump is mounted with the fuel heater and primary ﬁlter in the Horizontal Fuel Conditioning Module (HFCM). The fuel pump relay, which is located in the Power Distribution Center (PDC), is controlled and monitored by the ECM.

Water separated from the fuel in the

• HFCM is detected by the Water-inFuel (WIF) sensor. The sensor is an input to the ECM, which controls the WIF dash lamp through the CAN 1 link.

The HFCM has both an electric fuel

• heater and a temperature controlled recirculation valve. The valve regulates recirculation through the system to assist the heater in warming the fuel. The secondary ﬁlter and fuel pressure regulator valve are mounted on the engine.

System Operation

Secondary fuel filter

HFCM

Cylinder heads

Fuel tan

Fuel injectors

Drilled passage

Check valve in

banjo bolt

Fuel pressure test port

Check valve in

banjo bolt

Drilled passage

Fuel return from engine to HFCM

Fuel supply to engine

Fuel return to tank

Fuel supply to HFCM

Primary fuel filter

Unfiltered fuel from the fuel tank

Conditioned fuel from HFCM to fuel filter

Conditioned fuel from fuel filter

The fuel pump, fuel heater, pressure relief valve,

• Water-in-Fuel (WIF) sensor, recirculation valve, water drain and primary ﬁlter are all located in the Horizontal Fuel Conditioning Module (HFCM). The secondary ﬁlter, pressure regulator and banjo bolts are mounted on the engine.

The ECM uses the fuel pump relay to activate

• the fuel pump at key-on. Fuel drawn from the tank contacts the electric fuel heater, passes through the one-way check valve, and enters the ﬁlter where water is separated. Fuel passes through the ﬁlter media and enters the pump inlet while water settles to the bottom of the housing until the level of water activates the WIF sensor. Pressurized fuel from the pump is routed to the engine-mounted ﬁlter. Fuel ﬂows through the ﬁlter, then through individual steel lines to the cylinder heads. Each line is attached to the cylinder head with a banjo bolt. Each bolt contains an oriﬁce and a check valve. Once in the head passages, fuel is distributed to the injectors.

FUEL SUPPLY SYSTEM

Fuel is exposed to the pressure regulator

• in the secondary ﬁlter housing. The regulator returns excess fuel to the HFCM where it is directed to either the fuel tank or the pump inlet, depending on fuel temperature.

Both ﬁlter elements push open a fuel passage

• valve when inserted into their respective housings. Without the ﬁlter in place, fuel will not ﬂow through the system. The engine could start without the ﬁlter, but will not run properly.

Horizontal Fuel Conditioning Module (HFCM)

The Horizontal Fuel Conditioning Module con-

• tains the fuel pump, fuel ﬁlter, WIF sensor, heater and the recirculation control valve. The water drain valve and all fuel connections are mounted on the module cover. The lower connection on the pump end of the module is the suction side to the tank and the lower connection on the ﬁlter side is pressure to the enginemounted ﬁlter.

PRESSURE TO

SECONDARY

FILTER

DRAIN PLUG

COVER

WIF CONNECTOR

PUMP CONNECTOR

SUCTION SIDE

FILTER

FUEL SUPPLY SYSTEM and DIAGNOSTIC TESTS

Primary Fuel Filter and Fuel Heater

RECIRCLULATION

CONTROL VALVE

HEATER

FILTER ELEMENT

FUEL PUMP

HEATER CONNECTOR

The HFCM contains a 10-micron primary fuel ﬁlter. The

• replaceable ﬁlter element opens a fuel passage in the end of the pump when the ﬁlter is inserted into the housing. Without the ﬁlter in place, sufﬁcient fuel will not pass through the system for correct engine operation.

Fuel from the tank is exposed to the electric fuel heater as

• it enters the HFCM module. The heater is controlled by the Key Switch start/run circuit and is selfregulating. The heater comes on when fuel temperature is below 50°F (10°C) and goes off at 80°F (27°C). Return fuel from the engine is recirculated to the suction side of the ﬁlter until the fuel temperature is sufﬁcient to cause the recirculation valve to close. After the valve closes, all returned fuel is directed back to the tank.

Secondary Fuel Filter

The secondary ﬁlter is a top-loaded, engine-mounted fuel

• ﬁlter. Fuel enters the ﬁlter housing under pressure from the fuel pump through the inlet line and banjo bolt. Fuel passes through the 4-micron ﬁlter element and through the ﬁlter stand pipe to enter the two fuel lines to the cylinder heads.

FILTER HOUSING

The ﬁlter standpipe contains a valve that is opened by the

• ﬁlter when it is installed in the housing. Without the ﬁlter in place, sufﬁcient fuel will not pass through the system for correct engine operation.

Measure Fuel Pressure

The engine will not perform correctly with low fuel pressure.

• Fuel pressure can be measured at the secondary ﬁlter housing by removing the fuel pressure test port plug and install the ICP System Test Adapter (ZTSE4594) (1). Connect the Fuel Pressure Gauge (ZTSE4681) (2) to the ICP System Test Adapter. Turn the Key Switch to the ON position and measure the fuel pressure. The following pressure minimums should be met:

Cranking 20 psi Idle 50 psi High Idle/No load 50 psi Full load @ rated speed 50 psi

If fuel pressure does not meet the minimum, verify there is

• fuel in the tank and the pump is running. Then check for fuel aeration, primary and secondary ﬁlter condition, pump inlet restriction, pump deadhead pressure, and pressure regulator operation.

DIAGNOSTIC TESTS

Check for Fuel Aeration

The engine will not operate correctly with aerated fuel. Aera-

• tion can be checked visually using a clear hose and valve.

With the Key Switch in the ON position, open the valve

• (3) to allow fuel to ﬂow into a clean container. Observe the fuel ﬂow (4). Opening the system to install the hose will allow some air to enter the system. This air will be visible in the fuel ﬂow initially but should clear within a few seconds.

If the fuel continues to show signs of aeration, check the

• suction side of the system for air leaks.

Measure Fuel Pump Discharge Pressure

Determine the ability of the fuel pump to develop pressure by

• isolating the fuel pump from the engine-mounted regulator.

Remove the banjo bolt (5) on the pressure line at the

• secondary fuel ﬁlter and insert the bolt through the back of the ﬁtting so that the bolt faces away from the engine. Install the Fuel Pressure Test Adapter (ZTSE4696) (6) and tighten the bolt. Attach a 0-160 psi Fuel Pressure Gauge (ZTSE4681) (2) to the test adapter. The fuel pump and its internal pressure regulator are now isolated from the engine-mounted fuel pressure regulator.

Turn the Key Switch to the ON position and measure the fuel

• pressure while the pump is running. Pump discharge pressure should reach 80 psi. If the pressure is low, check for a plugged primary ﬁlter and/or high pump inlet restriction.

Measure Fuel Inlet Restriction

High inlet restriction can starve the suction side

• of the fuel pump and cause low fuel pressure.

With the Key Switch in the OFF position, remove the wa-

• ter drain plug from the fuel pump. Install the Fuel Inlet Restriction Adapter (ZTSE4698) in place of the plug. Connect the 0-30 in/hg pressure gauge to the adapter with a shut off valve in the OFF position between the pump and the Fuel Pressure Gauge (ZTSE4681).

Turn the Key Switch to the ON position. With the

• fuel pump running, open the valve to the 0-30 in/ hg pressure gauge and record the restriction.

If inlet restriction causes a gauge reading of greater than

• 6 in/Hg, check the lines from the fuel tank to the pump for restrictions.

LUBRICATION

SYSTEM

Crankshaft driven lube oil pump

• Integrated oil cooler

• External oil pressure regulator

• Easy access canister oil ﬁlter

• Piston cooling jets

•

OIL FILTER

ADAPTER

System Features

The crankshaft driven oil pump is located behind the

• vibration damper and is integrated into the front cover.

The oil pressure regulator valve is located in the front

• cover below the oil pump. The oil pressure regulator valve is accessed by removing the pressure regulator end plug.

The oil cooler is located under the oil cooler cover

• within the engine’s Vee. The cooler occupies a portion of the space within the high-pressure reservoir.

GEROTOR OIL PUMP

OIL PRESSURE

REGULATOR

The oil ﬁlter is a canister style ﬁlter located on top of the engine.

•

System Operation

Oil that is sprayed through the piston cooling jets is

• used in order to reduce the piston crown temperatures.

Oil discharged from the oil pump enters the oil cooler cover.

• If the oil is cold and thick the cooler bypass valve directs the oil directly to the oil ﬁlter. After passing through the ﬁlter, oil returns to the cooler cover assembly and is directed to the crankcase passages where oil is directed to the crankshaft main bearings, camshaft, lifters, piston cooling jets, and the valve train components.

Oil Filter Bypass

LUBRICATION SYSTEM

The ﬁlter bypass valve is located at

• the top of the ﬁlter standpipe. The top of the oil ﬁlter element has a hole that matches the location of the valve. Unﬁltered oil surrounds the ﬁlter, including the top of the ﬁlter and the bypass valve. The valve opens if there is a pressure difference of 32 psi between the outside of the paper ﬁlter material, which is unﬁltered oil, and the inside of the ﬁlter paper.

Oil Filter

The VT 275 uses a cartridge style oil

• ﬁlter located on top of the engine.

FILTER BYPASS VALVE

STANDPIPE

OIL FILTER

HOUSING

When the oil ﬁlter is removed, the oil

• ﬁlter drain valve opens to allow oil to drain from the ﬁlter housing, through the adapter, and back to the oil pan. The oil ﬁlter element snaps onto the lid. This allows the ﬁlter element to be extracted without contact with the element.

Note: The oil ﬁlter lid should be re-

•

moved before draining the oil from the oil pan so that the oil can drain from the ﬁlter housing into the oil pan.

FILTER LID

FILTER ELEMENT

OIL FILTER

HOUSING

COOLING

SYSTEM

Modular water pump

• Stainless steel injector sleeves

• Stainless steel glow plug sleeves

• Extended life coolant

•

System Features and Flow

The modular water pump mounts in

• the front cover and draws coolant from the radiator via the coolant inlet on the front cover. The water pump pushes coolant through two ports on the front cover to matching ports on the crankcase. Coolant ﬂows through the crankcase and cylinder passages, then returns to the front cover. Coolant is then directed to the thermostat where coolant ﬂows to either the bypass port or the radiator, depending on the coolant temperature. Coolant leaving the water pump is also directed to the oil cooler where it travels between the plates of the oil cooler and then to the EGR cooler.

COOLING SYSTEM

Belt tensioner

Smooth idler pulley

Smooth

idler pulley

Grooved idler pulley

Alternator

Grooved idler pulley

Power

steering pump

Vibration Damper

A/C Compressor

Front Cover Flow

Coolant is drawn into the water inlet by

• the water pump. Coolant is discharged from the pump to the crankcase coolant jackets. Coolant is also routed from the front cover through a crankcase passage to the oil cooler cover.

Return coolant from the crankcase

• coolant jackets is directed to the thermostat by the front cover. If the thermostat is open, coolant ﬂows to the radiator to be cooled. If the thermostat is closed, coolant is returned to the water pump via a bypass circuit in the front cover.

Service Intervals

The VT 275 is designed to

• use Extended Life Coolants.

Extended life coolant can be identiﬁed

• by its red/orange color in contrast to conventional green or blue antifreeze.

The service interval is 5 years, 300,000

• miles or 12,000 hours if the chemical extender is added at 30 months, 150,000 miles, or 6000 hours.

FROM THE INTAKE MANIFOLD

TO RADIATOR

HEATER SUPPLY

HEATER RETURN

FROM THE RADIATOR

Service Intervals for the VT 275 Engine

_Change Oil and Filter *7,500 mi., or 6 months_ _Primary and Secondary Fuel Filter *22,500 mi., or 18 months_ _Coolant (Extended Life Coolant) 300,000 miles / 12,000 hours / 5 years_

(if extender is added at 30 months,_

150,000 miles, or 6,000 hours)_

Note: Do not add supplemental cool-

•

ant additives like DCA4 to long-life coolant.

Belt Routing

The VT 275 uses one accessory

• drive belt. The belt must be routed correctly for the proper operation of the cooling fan, alternator, water pump and power steering pump.

The engine uses a combination of

• grooved and smooth idler pulleys. The large diameter smooth pulley is located to the left of the engine’s center when viewed from the front.

The smaller smooth pulley is the lower

• idler on the right side of the front cover when viewed from the front of the engine.

SPECIAL TOOLS

ZTSE4698

Fuel Inlet Restriction

• Adapter

ZTSE4693

Relay Breakout Harness

• (ECM)

ZTSE4755

Relay Breakout Harness

• (IDM)

ZTSE4526

Fuel / Oil Pressure Test

• Coupler

ZTSE4542

Fuel Pressure Test Fitting

•

(used for oil pressure measurement)

ZTSE4594

ICP System Test Adapter•

ZTSE4754

APS Harness•

ZTSE4665

12-Pin Breakout Harness•

ZTSE7559

Vacuum Pump and Gauge•

ZTSE4681

Fuel Pressure Gauge•

ZTSE4696

Fuel Pressure Test Adapter•

Digital Multimeter•

HARD START / NO START

and PERFORMANCE

DIAGNOSTICS

= Hard Start / No Start Diagnostics

= Performance Diagnostics

Initial Ignition Key-ON Engine Cranking Diagnostic Trouble Codes Key-OFF Engine-OFF (KOEO) Standard Test Visual Inspection Engine Oil Fuel Supply System Main Power Relay Voltage to the ECM Main Power Relay Voltage to the IDM Glow Plug System Inlet Air Heater

WARNING: To avoid personal injury, death, or vehicle damage, refer to the safety Information in the beginning of this book before working on the vehicle.

CAUTION: Do the following checks in sequence unless stated otherwise. Doing a check or test out of sequence could cause incorrect results.

HARD START NO START and PERFORMANCE DIAGNOSTICS

Initial Ignition Key-ON

Purpose: Verify that the ECM and IDM are receiving battery power.

Tools: None.

WARNING: To avoid personal injury, death, or vehicle damage, refer to the Safety Information in the beginning of

this book before working on the vehicle.

1. Verify ECM Power

Turn the Key Switch to the ON position.

1. Check the WAIT TO START dash lamp. The dash lamp should come on before the other dash lamps self

2. test. Check for the following if the lamp does not operate correctly:

No key power (VIGN) to the ECM.

• Failed ECM ground circuit.

• No power from main power relay to the ECM.

• The CAN1 link is not working (will not cause hard start or no start).

• ECM failure.

• WAIT TO START lamp is defective (will not cause hard start or no start).

•

2. Verify IDM Power

Turn the Key Switch to the ON position and listen for the injector pre-cycle (All the injectors should buzz

1. together when the Key Switch is ﬁrst turned on). Check for the following if the pre-cycle does not occur:

No key power (VIGN) to the IDM or ECM.

• Failed IDM or ECM ground circuit .

• No power from main power relay to the IDM.

• CAN2 link is not working.

• IDM failure.

• ECM has a power or ground problem.

•

3. Check for Water In Fuel

Turn the Key Switch to the ON position.

1. Check the WATER-IN-FUEL dash lamp. The lamp should not stay on after the dash self test is

2. completed. Check for the following if the lamp is illuminated:

Water in fuel.

• Corroded housing or connectors (will not cause hard start or no start).

• Circuit failure (will not cause hard start or no start).

•

4. Check for Fuel Pump Operation

Turn the Key Switch to the ON position. Listen for a hum or buzz from the electric fuel pump after initial

1. key on; the pump should stay on for 60 seconds then cycle off if the engine was not started. Check for the following if the pump does not operate:

Faulty fuel pump relay or fuse.

• Fuel pump failure.

• No key power (VIGN) to the ECM.

• Wiring failure from ECM to relay.

• Wiring failure from relay to pump.

• ECM failure.

•

HARD START NO START and PERFORMANCE DIAGNOSTICS

Engine Cranking

Purpose: Verify the engine cranking speed is sufﬁcient to start the engine.

Tools:

EST with MasterDiagnostics® software (optional).

• EZ-Tech® interface cable (optional).

•

WARNING: To avoid personal injury, death, or vehicle damage, refer to the Safety Information in the beginning of this book before working on the vehicle.

See "Appendix A: VT 275 Performance Speciﬁcations" for speciﬁcations, and enter data in "Spec" column for rpm.

1. Check for Crankshaft Rotation

Turn the Key Switch to the START position. Monitor the rpm on the instrument panel and the Electronic

1. Service Tool (EST) if available. If the engine cranking speed is below the speciﬁcation, do not continue with additional testing until that problem is corrected. Check for the following if cranking speed is below speciﬁcation:

Low or no battery power.

• Insufﬁcient power to ECM.

• Starting system failure.

• Circuit fault for Engine Crank Inhibit (ECI).

• Cylinder hydraulic lock.

• Incorrect oil viscosity.

• Cold temperature.

•

2. Check for Exhaust Smoke

Check for exhaust smoke while trying to start the engine. Observe the tail pipe and note the color of any

1. exhaust smoke. Check for the following if excessive smoke occurs while cranking:

Glow plug system failure.

• Failed air heater system.

• Poor fuel quality.

• Excessive air inlet or exhaust restriction.

• Low cylinder temperature.

• Loose injector.

• Low compression.

•

NOTE: If smoke is seen, typically excess fuel is getting in the cylinders.

NOTE: The engine may run rough and produce white smoke after the fuel ﬁlter has been serviced or the fuel system

opened. This occurs because air has entered the fuel system. This is normal and should stop after a short time.

HARD START NO START and PERFORMANCE DIAGNOSTICS

Diagnostic Trouble Codes

Purpose: Verify there are no active DTCs.

Tools:

EST with MasterDiagnostics® software (optional).

• EZ-Tech® interface cable (optional).

•

WARNING: To avoid personal injury, death, or vehicle damage, refer to the Safety Information in the beginning of this book before working on the vehicle.

1. Access DTCs

Set the parking brake

1. Turn the Key Switch to the ON position.

2. Move the cruise switch slide switch from OFF to R/A, and then release within 3 seconds.

3. DTCs will ﬂash on the red and amber lamps in the instrument panel.

2. Reading DTCs

Two types of DTCs are displayed; active and inactive. Both are three digit codes. The red lamp will ﬂash

1. once to indicate the beginning of the active DTCs, and then the amber lamp will ﬂash the ﬁrst digit of the ﬁrst DTC. The number of amber ﬂashes is the ﬁrst digit. After the ﬁrst digit there will be a short pause then the lamp will ﬂash the second digit.

Example: Two amber ﬂashes, a pause, three amber ﬂashes, a pause, and two amber ﬂashes and a pause indicates a DTC 232.

If there is more than one active DTC, the red lamp will ﬂash once indicating the beginning of another

2. active DTC. After all the active DTCs have been displayed, the red lamp will ﬂash twice to indicate the start of

3. inactive DTCs. After all DTCs have been ﬂashed the red lamp will ﬂash 3 times.

Active DTCs: Active indicates a DTC for a condition currently in the system.

• Inactive DTCs: Inactive indicates a DTC for a condition during a previous key cycle.

• Active/Inactive: Active/inactive indicates a DTC that is active now and was present in the last

• key cycles if the codes were not cleared.

HARD START NO START and PERFORMANCE DIAGNOSTICS

Key-OFF Engine-OFF (KOEO) Standard Test

Purpose: Verify there are no active DTCs after the KOEO Standard test.

Tools:

EST with MasterDiagnostics® software (optional)

• EZ-Tech® interface cable (optional)

•

WARNING: To avoid personal injury, death, or vehicle damage, refer to the Safety Information in the beginning of this book before working on the vehicle.

1. Perform Standard Test using MasterDiagnostics®

Set parking brake.

1. Turn Key Switch to ON. (Do not crank engine.)

2. Select Diagnostics from the menu bar.

3. Select Key-On Engine-Off Tests from the drop down menu.

4. From the KOEO Diagnostics menu, select Standard, then select Run to start the test. When the test is

5. completed, the DTC window will show DTCs if a problem has been detected.

2. Perform standard test using the cruise switches

Use the following method to check the DTCs if MasterDiagnostics® is not available:

Set the parking brake.

1. Turn Key Switch to ON. (Do not crank the engine.)

2. Move slide switch from OFF to R/A and then release.

3. Move slide switch to R/A within three seconds and standard test will run.

4. DTCs will be displayed through the red and amber engine dash lamps.

Note: The following actuators are tested during the Standard test:

241 Injection Pressure Regulator (IPR) solenoid or IPR control circuit.

• 238 Inlet Air Heater (IAH) relay coil or relay control circuit.

• 251 Glow plug relay coil or relay control circuit.

• 237 Fuel pump relay coil or relay control circuit.

•

HARD START NO START and PERFORMANCE DIAGNOSTICS

Visual Inspection

Purpose: Verify that there is no visible damage to the engine systems.

Tools: • Inspection lamp

WARNING: To avoid personal injury, death, or vehicle damage, refer to the Safety Information in the beginning of

this book before working on the vehicle.

1. Check for fuel, oil, and coolant leaks that may indicate more extensive engine damage.

2. Check the Electrical System

Check the relays and control module connections. All connections must be seated, in good condition,

1. and free of damage or corrosion. Check the glow plug relay and IAH relay for corrosion.

2. Check battery cable connections for corrosion. All connections must be seated, in good condition, and

3. free of damage or corrosion. Check engine wiring harness for correct routing and protection against rubbing or chafﬁng.

3. Check the Engine Sensors and Actuators

The engine will not start if the following components are disconnected or damaged:

Injection Pressure Regulator (IPR) valve

• Camshaft Position (CMP) sensor

• Crankshaft Position (CKP) sensor

•

4. Check the Filter Minder

When the ﬁlter element reaches maximum allowable restriction, the indicator will reach the top of the

1. window and automatically lock in this position.

5. Inspect the following parts for restriction, damage or incorrect installation:

•

Air ﬁlter inlet and duct. • Exhaust pipes.

•

Air inlet hoses and clamps. • Chassis mounted CAC and piping. Air ﬁlter housing, ﬁlter element, and gaskets. • Air ﬁlter restriction indicator (if equipped).

• Boost control solenoid hose harness

•

NOTE: Unﬁltered air will cause accelerated engine wear.

If leaks in the air induction system are suspected, check for air ﬁlter element end seal movement inside the housing. End seal movement is indicated, if the seal contact area is polished.

NOTE: Intake restriction should be below 6.2 kPa (25 in H2O) at full load condition. Intake restriction performed for this test at high idle should be below 3.1 kPa (12.5 in H2O).

6. Check for exhaust system restriction

Inspect the entire exhaust system for bent, damaged, or kinked exhaust pipes. The following can cause a

1. no-start condition:

Tailpipe or mufﬂer may be damaged or collapsed.

• Plugged or restricted Catalytic converter - if equipped.

•

HARD START NO START and PERFORMANCE DIAGNOSTICS

Engine Oil

Purpose: Verify the engine has the correct oil level for injector operation.

Tools: None.

WARNING: To avoid personal injury, death, or vehicle damage, refer to the Safety Information in the beginning of

this book before working on the vehicle.

NOTE: Never check the oil level when the engine is running or immediately after engine shutdown; the reading will be inaccurate. Allow 15 minute drain down time, before checking oil level.

NOTE: If the oil level is too low, the fuel injectors will not work correctly. If the oil level is above the operating range, the engine has been incorrectly serviced, fuel is in the oil, or coolant is in the oil.

1. Check Engine Oil

Check the engine oil level with the vehicle on parked on level ground after the engine has been off for at

1. least 15 minute. Check for the following if the oil level is incorrect:

Low oil level.

• Oil leak.

• Oil consumption.

• Incorrect servicing.

• High oil level.

• Fuel in oil.

• Coolant in oil.

• Incorrect oil level gauge.

•

2. Check Oil for Contamination

Check the oil for the thickening. Oil contaminated with long life coolant will cause thickening or

1. coagulation. Does oil have a diesel fuel odor?

2. Check engine service records for correct oil grade and viscosity for ambient operating temperatures.

3. See "Lubrication Requirements" in the Engine Operation and Maintenance Manual (for engineís model

4. number and model year). Conﬁrm that oil meets correct API category.

CAUTION: Do not use 15W-40 oil below -7 ºC (20 ºF). Long oil drain intervals can increase oil viscosity; thicker oil will make engine cranking and starting more difﬁcult below freezing temperatures.

HARD START NO START and PERFORMANCE DIAGNOSTICS

Fuel Supply System

Purpose: Verify that the fuel system is producing the correct pressure.

Tools:

0-160 psi gauge

• ICP System Test Adapter

• In-line shut off valve

• 3/8 inch clear sample line

• Clear container with a wide opening

•

WARNING: To avoid personal injury, death, or vehicle damage, refer to the Safety Information in the beginning of this book before working on the vehicle.

See EGES 305-1 "Appendix A: VT 275 Performance Speciﬁcations" (page 579) for fuel pump pressure speciﬁcation and record on Diagnostic Form.

1. Verify the Fuel Quantity

Check the fuel level in fuel tank. Check the fuel tank for odors of kerosene, alcohol, or gasoline.

2. Verify Fuel Pump Operation

Turn the Key Switch to the ON position; listen for a hum coming from the fuel pump. The ECM turns the

1. pump on; it should run for 60 seconds. After 60 seconds the ECM turns the pump off unless the engine is running. See page 35 for additional diagnostic steps if the pump cannot be heard running.

NOTE: The engine may run without the fuel pump, but damage to the injectors could occur.

3. Taking a Fuel Sample

Place a container under the secondary fuel ﬁlter test port plug.

1. Remove the plug.

2. Use the ICP System Test Adapter to attach the 160 psi pressure gauge to the port.

3. Run the clear test line to a clear container, and then turn the Key Switch to the ON position.

4. Open the in-line shut off valve to collect the fuel sample.

5. Check the test line for air bubbles while the pump is operating.

6. Check the sample for contamination.

NOTE: Breaking any fuel system joints will induce air in the fuel system. The air bubbles should stop shortly. A continuous ﬂow of bubbles can indicate a leak on the suction side of the system.

4. Measure Engine Fuel Pressure

Close the in-line shut off valve.

1. Turn the Key Switch to the ON position and check the fuel pressure gauge when the pump starts:

If fuel pressure is below speciﬁcation, replace both the primary and secondary fuel ﬁlters and

• retest. If the engine fuel pressure is still below speciﬁcation, measure the fuel pump's discharge

• pressure.

HARD START NO START and PERFORMANCE DIAGNOSTICS

Fuel Supply System CONTINUED

5. Measuring Fuel Pump Discharge Pressure

Place a suitable container under the secondary fuel ﬁlter housing banjo bolt (2).

1. Remove the bolt and connect the Fuel Pressure Test Adapter to the fuel supply line, using the banjo bolt

2. and original copper gaskets.

NOTE: Use existing copper gaskets from the banjo bolt for testing. Replace the copper gaskets when testing is over and repairs have been made.

Turn the Key Switch to the ON position.

3. Read the fuel pressure gauge.

If the pump discharge pressure is within speciﬁcations, the fuel pump is good. The low engine

• fuel pressure is the result of a restricted line from the pump to the engine or the pressure regulator valve in the secondary ﬁlter housing is stuck open. If the pump discharge pressure is low, check the pump inlet restriction.

•

6. Measuring Pump Inlet Restriction

Put a clean drain pan under the fuel pump drain plug.

1. Clean the drain plug and the area around the plug.

2. Open the drain plug and drain the pump.

3. Install the fuel inlet restriction adapter hand tight.

4. Connect a 0-30 in. Hg Gauge to the adapter through an in-line shut off valve.

5. Close the valve.

6. Turn the Key Switch to the ON position and open the shutoff valve.

7. Check the gauge reading:

If the reading is above 6 in. Hg, check for a restriction in the fuel line between the pump and the

• tank pick-up opening. If reading is below the speciﬁcation when the fuel pump discharge pressure is low, the fuel

• pump is faulty.

HARD START NO START and PERFORMANCE DIAGNOSTICS

Main Power Relay Voltage to the ECM

Purpose: Verify that the ECM is receiving a minimum of seven volts.

Tools:

12-Pin Breakout Harness

• Digital Multi-Meter (DMM)

•

WARNING: To avoid personal injury, death, or vehicle damage, refer to the Safety Information in the beginning of this book before working on the vehicle.

NOTE: Batteries must be fully charged before performing the following tests.

1. Measure Voltage supplied to the ECM Turn the Key Switch to OFF.

1. Remove the ECM relay from the power distribution center.

2. Install the ECM Relay Breakout Harness between the main power relay and the power distribution

3. center. Connect the positive DMM lead to pin 87 and the DMM negative lead to a good ground.

4. Measure the voltage while cranking the engine for 20 seconds. The Voltage should not go below 7 volts.

5. Check for the following if the relay provides less than 7 volts to the ECM:

Discharged batteries.

• Corroded or loose connections.

• Failed batteries.

• High-resistance at battery cable connections.

• The ECM main power fuse in the power distribution center may be open.

• High-resistance or an open power feed circuit to the ECM or ECM power relay.

• Failed ECM main power relay.

• Key Switch circuit problem failed fuse.

• Low or no battery voltage to the ECM.

• Failed ECM.

•

2. If the voltage is low, go to "ECM Power Relay" diagnostics, page 25.

HARD START NO START and PERFORMANCE DIAGNOSTICS

Main Power Relay Voltage to the IDM

Purpose: Verify that the IDM is receiving a minimum of seven volts.

Tools:

12-Pin Breakout Harness

• Digital Multi-Meter (DMM)

•

WARNING: To avoid personal injury, death, or vehicle damage, refer to the Safety Information in the beginning of this book before working on the vehicle.

NOTE: Batteries must be fully charged before performing the following tests.

1. Measure the Voltage supplied to the IDM Turn the Key Switch OFF.

1. Disconnect the 12-pin chassis harness to engine harness connector.

2. Connect the 12-Pin Breakout harness between both connectors.

3. Connect the DMM positive lead to Pin 12 (IDM PWR) and the negative lead to pin 1(IDM GND).

4. Measure the voltage while cranking the engine for 20 seconds. The voltage should not go below 7 volts.

5. Check the following if the IDM relay supplies less that 7 volts to the IDM:

High-resistance at battery cable connections.

• Low battery voltage.

• Corroded or loose connections.

• Open Wiring to the IDM.

• The IDM fuse open.

• Failed IDM relay.

• Failed IDM.

•

2. If the voltage is low, go to "IDM Power Diagnostics", page 27.

HARD START NO START and PERFORMANCE DIAGNOSTICS

Glow Plug System

Purpose: Verify that the glow plug system is operating correctly.

Tools:

EST with MasterDiagnostics® software (optional)

• EZ-Tech® interface cable (optional)

• Digital Multi-Meter (DMM)

• Amp Clamp

•

WARNING: To avoid personal injury, death, or vehicle damage, refer to the Safety Information in the beginning of this book before working on the vehicle.

1. Measure the left bank AMP draw

Install the inductive lead of an ammeter or Amp Clamp around the feed wire loom for the left bank glow

1. plugs. Turn the Key Switch to the ON position.

2. After 40 seconds, measure the amperage.

3. Turn the Key Switch OFF. The amp draw should be 24-42 amps.

2. Measure the Right bank AMP draw

Install the inductive lead of an ammeter or Amp Clamp around the feed wire loom for the right bank glow

1. plugs. Turn the Key Switch to the ON position.

2. After 40 seconds, measure the amperage. The amp draw should be 24-42 amps:

If the amperage on both banks is to speciﬁcation and no glow plug related DTCs were set, the

• glow plug system is working correctly and is not the starting problem. If the amperage is low, measure the resistance of each glow plug on the low bank.

•

3. Measure individual glow plug resistance

Disconnect the three pin connector from the bank with low amperage draw.

1. Use a DMM to measure the resistance of each pin through the glow plug to ground.

If a circuit has more than 6 ohms, disconnect the harness from the glow plug and check the

• resistance from the glow plug to ground. If a glow plug has more than 6 ohms, the plug is defective

•

4. The following are possible causes of low amperage draw: Poor wiring harness connection.

• Poor ground connection.

• Failed glow plug relay.

• Failed glow plugs.

• Failed ECM.

•

HARD START NO START and PERFORMANCE DIAGNOSTICS

Inlet Air Heater

Purpose: Verify that the Inlet Air Heater system is operating correctly

Tools:

EST with MasterDiagnostics® software (optional)

• EZ-Tech® interface cable (optional)

• Digital Multi-Meter (DMM)

• Amp Clamp

•

WARNING: To avoid personal injury, death, or vehicle damage, refer to the Safety Information in the beginning of this book before working on the vehicle.

1. Measure Inlet Air Heater amperage draw

Install the inductive lead of an ammeter or Amp Clamp around the lead to the Inlet Air Heater element.

1. Turn Key Switch to the ON position.

2. After 5 seconds, measure the amperage:

If amperage is 50+/- 5 amps and no inlet air heater DTCs were set, the IAH system is working

• correctly and is not the starting problem. If the amperage is not to speciﬁcation, measure the voltage at the element.

•

2. Measure element voltage during operation

Connect the DMM positive lead to IAH element terminal.

1. Connect the DMM negative lead to the alternator ground.

2. Turn Key Switch to the ON position. The element should have approximately battery voltage:

If the amperage draw is low and the voltage is OK, the element is at fault.

• If the amperage is low and the voltage is low, check for high resistance in the circuit supplying

• the element.

3. The following are possible causes of low amperage draw:

Poor wiring harness connection.

• Poor ground connection.

• Failed relay.

• Failed element.

• Failed ECM.

•

DIAGNOSTIC TROUBLE CODES for WORKHORSE CHASSIS APPLICATIONS

Consult service literature for latest information before attempting any repairs.

l = Code is applicable to Workhorse Chassis

W DTC CIRCUIT C ONDITION DES CRI PTION COM M ENTS P ROBABLE CAUSES

111 ECM No errors - ﬂash code only Instrument panel code only, retrieving

l 112 ¸

l 113 ¸

114 * ECT Engine Coolant Temperature signal out

115 * ECT Engine Coolant Temperature signal out

121 * MAP Intake Manifold Absolute Pressure signal

122 * MAP Intake Manifold Absolute Pressure signal

123 * MAP Intake Manifold Absolute Pressure signal

124 * ICP Injection Control Pressure signal out of

125 * ICP Injection Control Pressure signal out of

126 * BCP Engine Brake Control Pressure signal

127 * BCP Engine Brake Control Pressure signal

l 131 * ¸

l 132 * ¸

l 133 * ¸

l 134 * ¸

l 135 * ¸

136 EFP Engine Fuel Pressure signal out of range

137 EFP Engine Fuel Pressure signal out of range

l 141 ¸

l 142 ¸

143 CMP Incorrect CMP signal signature CMP signal intermittent Poor connection, failed sensor, electri-

145 CMP CMP signal inactive No start, No CMP signal, while CKP

146 CMP CMP signal inactive No start, No CMP signal, while CKP

ECM PWR Electrical system voltage B+ out of

range high

ECM PWR Electrical system voltage B+ out of

range low

of range low

of range high

out of range high

out of range low

in-range fault

range low

range high

out of range low

out of range high

APS/IVS Accelerator Position Sensor signal out of

range low

APS/IVS Accelerator Position Sensor signal out of

range high

APS/IVS Accelerator Position Sensor signal in-

range fault

APS/IVS Accelerator Position Sensor signal and

Idle Validation switch disagree

APS/IVS Idle Validation Switch circuit fault 50% APS only, APS / IVS conﬂict Failed IVS signal

low

high

VSS Vehicle Speed Sensor signal out of

range low

VSS Vehicle Speed Sensor signal out of

range high

DTCs using cruise switches

ECM voltage continuously > 23.2v Charging system fault

ECM voltage < 7v - cause of no start/rough idle

Default 180 °F / 82 °C - no fast idle, < 0.127v

Default 180 °F / 82 °C - no fast idle, < 4.6v

Default inferred MAP - low power, slow acceleration, > 4.9v

Default inferred MAP - low power, slow acceleration, < 0.039v

Default inferred MAP - low power, slow acceleration

Default open loop control - under run at idle, < 0.039v

Default open loop control - under run at idle, > 4.9v

Engine Brake disabled, < 0.039v BCP circuit OPEN or short to GND,

Engine Brake disabled, > 4.9v BCP circuit short to PWR, failed

Engine idle only, < 0.147v APS circuit OPEN or short to GND,

Engine idle only, > 4.55v APS circuit short to PWR, engine

Engine idle only, APS / IVS conﬂict Failed APS signal

Engine idle only, APS / IVS conﬂict Both APS and IVS signal failure

Fuel Filter restriction indication disabled, < 0.039v

Fuel Filter restriction indication disabled, > 4.9v

Speedo, cruise, PTO disabled - eng. RPM limited - signal frequency, <

0.048v

Speedo, cruise, PTO disabled - eng. RPM limited - signal frequency, >

0.048v

signal active and/or ICP signal above engine speciﬁc set point

No faults detected by the ECM

Low VBAT, loose connection/resistance in circuit

ECT circuit short to GND, failed sensor

ECT circuit OPEN or short to PWR, failed sensor

MAP circuit short to PWR, failed sensor

MAP circuit OPEN or short to GND, failed sensor

MAP sensor plugged, failed sensor

ICP circuit OPEN or short to GND, failed sensor

ICP circuit short to PWR, failed sensor

failed sensor

sensor

defective sensor

VREF concern, defective sensor

EFP circuit OPEN or short to GND, failed sensor

EFP circuit short to PWR, failed sensor

VSS circuit OPEN or short to GND

VSS circuit short to PWR or engine VREF concern

cal noise

CMP circuit OPEN, short to GND or PWR, failed sensor

¸ See Chassis Circuit Diagrams and Engine Diagnostics Manual for more information. * Indicates Amber ENGINE lamp on when a Diagnostic Trouble Code (DTC) is set. ** Indicates Red ENGINE lamp on when Engine Warning Protection System (EWPS) is enabled and a DTC is set.

DIAGNOSTIC TROUBLE CODES for WORKHORSE CHASSIS APPLICATIONS

W DTC CIRCUIT C ONDITION DES CRI PTION COM M ENTS P ROBABLE CAUSES

147 CKP Incorrect CKP signal signature CKP signal intermittent Poor connection, failed sensor, electri-

148 * MAF Mass Air Flow signal frequency out of

149 * MAF Mass Air Flow signal frequency out of

l 152 * ¸

l 153 ¸

l 154 * ¸

l 155 * ¸

161 * MAT Manifold Air Temperature signal out of

162 * MAT Manifold Air Temperature signal out of

163 * EGR Exhaust Gas Recirculation valve position

164 EGR Exhaust Gas Recirculation valve position

166 * MAF Mass Air Flow Sensor signal in-range

167 * MAF Excessive Mass Air Flow MAF signal setpoint above excessive

211 * EOP Engine Oil Pressure signal out of range

212 * EOP Engine Oil Pressure signal out of range

l 215 ¸

l 221 ¸

l 222 ¸

224 Flash Flash memory fault Internal Proprietary Flag Internal Proprietary Flag

225 EOP Engine Oil Pressure signal in-range fault EWPS disabled, EOP signal above

231 ATA ATA data communication link error EST communication disabled ATA defective grounded or overloaded

l 236 ¸

l 237 ¸

l 238 ¸

241 ¸

BAP Barometric Absolute Pressure signal out

WIF Water In Fuel Sensor signal out of range

IAT Intake Air Temperature signal out of

VSS Vehicle Speed Sensor signal out of

SCCS Speed Control Command Switches

BRAKE Brake switch circuit fault Voltage at ECM (BNO1) and (BNO2)

ECL Engine Coolant Level switch circuit fault EWPS disabled, < 4.3v tank full, >

FPC Fuel Pump Control OCC self test failed FPC output circuit check - engine off

IAH Inlet Air Heater Control (V6) OCC self

IPR Injection Control Pressure Regulator

range low

range high

of range low

high

range low

range high

range low

range high

signal out of range low

signal out of range high

fault

low

high

range high

- cruise-PTO circuit fault

test failed

OCC self-test failed

Default inferred MAF, EGR disabled, < 200Hz

Default inferred MAF, EGR disabled, > 11500Hz

Default 101 kPa, < 1.0v BAP circuit OPEN or short to GND,

Water in Fuel lamp disabled, >4.5v WIF circuit short to PWR

Default 77 °F / 25 °C, < 0.127v IAT circuit short to GND, defective

Default 77 °F / 25 °C, > 4.6v IAT circuit OPEN or short to PWR,

EGR disabled, < 0.098v MAT circuit short to GND, failed

EGR disabled, > 4.6v MAT circuit OPEN or short to PWR,

EGR disabled (2002-03 VT 365 only, < 0.3v), All 2004-up error message position

EGR disabled (2002-03 VT 365 only, > 4.8v)

MAF signal above calibrated limit KOEO, MAF sensor out of calibrated limit KOER

calibrated limit

EWPS disabled, default 50 psi, <

0.039v

EWPS disabled, default 50 psi, >

4.9v

Speedo, cruise, PTO disabled - eng. RPM limited - signal frequency, > 4365 Hz

SCCS signal incorrect, voltage signal wrong for switch state

are different

spec. with KOEO, > 26 psi/1.90v

3.4v tank empty

test only, engine power loss

IAH output circuit check - engine off test only, starting concern

IPR output circuit check - engine off test only; starting concern

cal noise

MAF circuit OPEN or short to GND

MAF sensor defective, noise interference

defective sensor

sensor

defective sensor

sensor

failed sensor

EGRP circuit OPEN or short to GND, failed sensor - position PWR or GND

EGRP circuit short to VREF or VBAT, failed sensor

Plugged or leaking intake or exhaust, biased MAF sensor

MAF circuit OPEN, short to GND or PWR, biased MAF sensor

EOP circuit OPEN or short to GND, failed sensor

EOP circuit short to PWR, failed sensor

Misadjusted/defective speed sensor, electrical noise

Short or resistance in SCCS circuit or CAN message fault

Fault / misadjusted switch, unsuccessful start after 20 seconds

EOP circuit OPEN or short to GND, defective sensor

ECL circuit, high resistance, defective sensor

FPC circuit OPEN or short to GND, high resistance

IAH circuit OPEN or short to GND, high resistance

IPR circuit OPEN, short to GND or PWR, failed IPR

DIAGNOSTIC TROUBLE CODES for WORKHORSE CHASSIS APPLICATIONS

W DTC CIRCUIT C ONDITION DES CRI PTION COM M ENTS P ROBABLE CAUSES

l 246 ¸

l 247 ¸

l 251 ¸

l 256 ¸

l 259 ¸

261 ¸

l 263 ¸

264 EGR Exhaust Gas Recirculation OCC self-test

l 266 ¸

l 268 ¸

311 * EOT Engine Oil Temperature signal out of

312 * EOT Engine Oil Temperature signal out of

313 ** EWPS Engine Oil Pressure below warning level ECM detects low oil pressure, engine

314 ** EWPS Engine Oil Pressure below critical level ECM detects low oil pressure, engine

l 315 * ¸

316 EWPS Engine Coolant Temperature unable to

321 ** EWPS Engine Coolant Temperature above

322 ** EWPS Engine Coolant Temperature above criti-

323 ** EWPS Engine Coolant Temperature belo warn-

324 ** IST Idle Shutdown Timer enabled engine

325 EWPS Power reduced, matched to cooling

331 * ICP SYS Injection Control Pressure above system

332 * ICP Injection Control Pressure above spec.

EFAN Engine Fan - OCC self test fault Fan relay - output circuit check - en-

BSV Engine Brake Enable OCC self-test

failed

GPC/IAH Glow Plug (V8 & V6) Inlet Air Heater (I6)

control OCC self test failed

RSE Radiator Shutter Enable OCC self test

failed

TCM TCM transmitted OSS fault TCM fault message received See diagnostic manual for transmis-

VGT Variable Geometry Turbo control OCC

self-test failed

OWL Oil/Water Lamp OCC self test failed Oil/Water Lamp - output circuit check

failed

WEL Warn Engine Lamp OCC self test failed Warn Engine Lamp - output circuit

ACC Air Conditioner Control OCC self test

failed

range low

range high

EWPS Engine speed above warning level ECM recorded excessive engine

reach commanded set point

warning level

cal level

ing/critical level

shutdown

system performance

working range

with KOEO

gine off test only

Brake Shut Off Valve output circuit check - engine off test only

GP/IAH relay - OCC test only - starting concern

Shutter relay - output circuit check

- engine off test only

VGTC - output circuit check - engine off test only

- engine off test only

EGRC output circuit check - engine off test only (2002-03 VT 365 only)

check - engine off test only

ACC - output circuit check - engine off test only

Default 212 ºF / 100 ºC, no fast idle < 0.2v

Default 212 ºF / 100 ºC, no fast idle > 4.78v

(red) lamp

(red) lamp; shutdown (if equipped)

speed - engine speciﬁc

Enabled only when cold ambient protection enabled

ECM detects high coolant temp, engine (red) lamp; temp engine speciﬁc

ECM detects high coolant temp, engine (red) lamp; temp engine speciﬁc, shutdown (if equipped)

ECM detects high coolant level, engine (red) lamp; shutdown (if equipped)

Engine shutdown, engine (red) lamp, only when enabled

ECM detects high coolant temperature; temp engine speciﬁc, power reduced

Default inferred ICP, max ICP range is engine speciﬁc

ICP signal volt higher than expected with KOEO, default inferred ICP

EFAN circuit OPEN, short to GND or PWR, defective relay

Brake Shut Off Valve circuit OPEN or short to GND, high resistance

Relay circuits OPEN, short to GND or PWR, failed relay

RSE circuit OPEN, short to GND or PWR, defective relay

sion

VGT circuits OPEN, short to GND or PWR, failed VGT module

Oil/Water Lamp circuit OPEN or short to GND, high resistance or failed lamp

EGRC circuit OPEN or short to GND or PWR, failed sensor

Warn engine lamp circuit OPEN or short to GND, high resistance or failed lamp

ACC circuit OPEN, short to GND or PWR, high resistance

EOT circuit short to GND, failed sensor

EOT circuit OPEN or short to PWR, failed sensor

EOP circuit fault, defective switch/ sensor, low oil pressure

Transmission improperly downshifted

Cooling system concern

Low coolant level, ECL circuit short to GND

Engine at low idle longer than IST programmed value

Cooling system concern

See diagnostic manual - ICP system

ICP signal GND circuit OPEN, failed sensor

DIAGNOSTIC TROUBLE CODES for WORKHORSE CHASSIS APPLICATIONS

W DTC CIRCUIT C ONDITION DES CRI PTION COM M ENTS P ROBABLE CAUSES

333 * ICP SYS Injection Control Pressure above/below

334 ICP SYS ICP unable to achieve setpoint in time

335 ICP SYS ICP unable to build pressure during

341 * EBP Exhaust Back Pressure signal out of

342 * EBP Exhaust Back Pressure signal out of

343 * AMS Excessive Exhaust Back Pressure

344 * EBP Exhaust Back Pressure above spec.

345 AMS Faults detected during VGT portion of

346 AMS Faults detected during EGR portion of

347 EBP Exhaust Back Pressure not responsive Sensor is not responsive due to icing Engine concern, plugged tube, failed

351 * AMS Exhaust Back Pressure did not change

353 * AMS Variable Geometry Turbo control over

354 * AMS Variable Geometry Turbo control under

355 AMS Variable Geometry Turbo overspeed Inferred overspeed based off of BAP,

361 * AMS VGT control circuit (MAP/EBP) above /

365 * AMS EG R Valve Position above/below desired

367 AMS Improper position signal when EGR

368 ¸

371 EFP Engine Fuel Pressure is above normal

372 EFP Engine Fuel Pressure is below normal

l 373 ¸

l 374 ¸

AMS EGR Drive Module/ECM2 communica-

IAH Inlet Air Heater relay circuit fault IAH relay output does not match

FPC Fuel Pump relay circuit fault FPC relay output does not match

desired level

(poor performance)

cranking

range low

range high

(gauge)

when engine off

the AMS Test

when expected

duty cycle

below desired level

level

valve is expected closed

tion fault

operating range

ICP desired does not = ICP signal, (difference is engine speciﬁc), default inferred ICP

No start (Min ICP is engine speciﬁc) See diagnostic manual - ICP system

EGR disabled, default inferred VGT < 0.039v

EGR disabled, default inferred VGT > 4.9v

EGR disabled (Max pressure is engine speciﬁc)

EGR disabled, default inferred VGT EBP signal GND circuit OPEN, failed

ECM did not detect expected change in EBP, VGT portion of AMS test only

ECM did not detect expected change in EBP, EGR portion of AMS test only

Delta pressure is insufﬁcient between KOEO and KOER minimum set point

ECM overcompensates by increasing duty cycle offset

ECM overcompensates by decreasing duty cycle offset

RPM and MAP

MAP /EBP actual does not = MAP / EBP desired

EGR disabled, EGRP actual does not = EGRP desired

EGR disabled, > 2.5 with key on engine off (2002-03 VT 365 only) should not see after programming

ECM lost communication from the EGR Drive Module

Will not illuminate any lamp - Speed and load dependent

Will illuminate FUEL FILTER lamp

- Speed and load dependent

desired

See diagnostic manual - ICP system

EBP circuit OPEN or short to GND, failed sensor

EBP circuit short to PWR, failed sensor

See diagnostic manual - Air Management System Note: No sensor

sensor

See diagnostic manual - Air Management System

sensor

Plugged EBP tube, stuck open EGR valve, exhaust system leak, bias

See diagnostic manual - Air Management System

See diagnostic manual - Air Management System See FAQ/TSI

EGR D-Module check circuits for OPEN or short to GND or PWR

See diagnostic manual - Fuel Pressure

Restricted fuel ﬁlter - See diagnostic manual - Fuel Pressure

IAH PWR feed circuit OPEN or high resistance, IAH diagnostic wire OPEN or high resistance

FPC PWR feed circuit OPEN or high resistance, FPC diagnostic wire OPEN or high resistance

DIAGNOSTIC TROUBLE CODES for WORKHORSE CHASSIS APPLICATIONS

W DTC CIRCUIT C ONDITION DES CRI PTION COM M ENTS P ROBABLE CAUSES

l 375 ¸

421 - 428 INJ High side to low side open (cylinder

431 - 438 INJ High side shorted to low side open

451 - 458 INJ High side short to GND or PWR (cylin-

l 523 ¸

525 * IDM IDM fault internal IDM fault Defective IDM

l 533 ¸

l 534 ¸

543 * ECM/IDM ECM/IDM communications fault Loss of communication between ECM

546 * BSV/BCP Engine Brake Control Pressure is below

547 * BSV/BCP Engine Brake Control Pressure is above

551 ECM/IDM IDM CMPO signal inactive No CMPO signal, while CKPO signal

552 ECM/IDM IDM incorrect CMPO signal signature CMPO signal intermittent or incorrect Poor connection between ECM and

553 ECM/IDM IDM CKPO signal inactive No CKPO signal, while CMPO signal

554 ECM/IDM IDM incorrect CKPO signal signature CKPO signal intermittent or incorrect Poor connection between ECM and

613 * ECM ECM/IDM software not compatible Components changed in ﬁeld not

614 * ECM EFRC/ECM conﬁguration mismatch Programming problem FRC not programmed properly

621 * ECM Engine using mfg. default rating program

622 * ECM Engine using ﬁeld default rating Engine limited to lowest hp in family,

623 * ECM Invalid Engine Family Rating Code ECM not programmed properly ECM not programmed properly

624 ECM Field default active EFRC not supported in ECM programming concern / internal ECM

l 626 ¸

631 ECM Read Only Memory (ROM) self test fault ECM failure Failed ECM

632 ECM Random Access memory (RAM) CPU

655 ECM Programmable parameter list level

661 ECM RAM programmable parameter list is

664 ECM Calibration level incompatible Programming concern Programming concern

665 ECM Programmable parameter memory con-

GPC Glow Plug relay circuit fault Glow Plug relay output does not

number indicated)

(cylinder number indicated)

der number indicated)

IDM IDM KEY PWR voltage low IDM detects KEY PWR low < 7v Low batteries, loose connections /

IDM IDM relay voltage high IDM detects excessive voltage > 16v Charging system fault

IDM IDM relay voltage low IDM detects logic PWR low, < 7v Low batteries, loose connections /

expected range

engine

ECM PWR Unexpected reset fault ECM power reset ECM power concern,

self-test fault

incompatible

corrupt

tent corrupt

match desired

IDM detected an open injector circuit Injector circuit OPEN, failed injector

IDM detected a short in an injector circuit from high to low

IDM detected a short in an injector circuit to GND or PWR

and IDM

BCP is less than ICP, difference of 580 psi / 4 MPa

BCP is greater than BCP desired, difference of 653 psi / 4.5 MPa

active

compatible

Engine operates at a default engine speciﬁc HP

options not available

ECM failure Failed ECM

Programming concern / ECM memory concern

ECM failure Failed ECM

GPC PWR feed circuit OPEN or high resistance, FPC diagnostic wire OPEN or high resistance

Injector circuit short high to low, failed injector

Injector circuit short to GND or PWR, failed injector

resistance in circuit, defective relay

IDM power concern, CAN2 circuit OPEN, short to GND or PWR

See diagnostic manual - Brake ShutOff Valve and BCP sensor

CMPO circuit OPEN, short to GND or PWR, logic power low

IDM

CKPO circuit OPEN, short to GND or PWR, logic power low

IDM

Components changed in ﬁeld not compatible

ECM not programmed

Calibration does not match EFRC

concern

low battery charge

Programming concern

Programming concern / internal ECM concern

POWER DISTRIBUTION CENTER

SPARE

10A

SPARE

15A

SPARE

IGN-RUN

IGN-

RUN/CRANK

BACK-UP

20A

CLEAN POWER

40A

IGN-A

50A

IGN-B

80A

BATTERY

60A

LIGHTING

30A

ABS PUMP

PARK

ETP

LH-TAIL

RH-TAIL

ACC-RUN

ABS-PUMP

20A

STOP

20A

AUX FAN

10A

BRAKE

10A

PCM BAT

ABS IGN

20A

FUEL PUMP

CRUISE

10A

TCM BAT

PCM IGN

EXTRACTOR

FUSE

ABS

RETARDER

ECM

(& NKC)

REMOTE KEY

15A

HAZARD

30A

BLOWER

10A

A/C COMP

10A

DATA

10A

TCM IGN

CRANK

20A

FUEL HTR

10A

IDM LOG

(& NKC)

IGN-RUN

ABS

W/L

BTS1

IDM

BLOWER

FUEL

PUMP

A/C

COMP

20A

SPARE

30A

SPARE

25A

ABS BAT

40A

IDM BAT

30A

A-STUD

30A

B-STUD

AUX-A AUX-B

AUX FAN STARTER

ENGINE & CHASSIS SCHEMATIC

ECT

IPR

actuator

EOT

MAT

EOP

switch

ICP

MAF/IAT

sensor

BCS

actuator

MAP

EGR valve

controller

Mitsubishi

EGR Valve

CKPO

IGN

IAH relay

To battery

power feed

on starter

To battery power

feed on starter

Glow plug

relay

Glow plugs

7EDCB

CAN 2 (+)

R-LG

CAN 2 (+)

CAN 2 (-)

IDM MPR

IDM LOGIC PWR

IDM MAIN PWR

ATA (+)

IDM GND

ATA (-)

ACT PWR

CAN 2 (-)

ACT PWR GND

DB-LG

LB-W

Sensor Supply Ground

Position Sensor (W Phase)

Position Sensor (V Phase)

Position Sensor (U Phase)

Sensor Supply

R-PK

Y-W

O-W

BR-W

BK-PK

231

11212

X3-5

X3-10

X3-30

X3-31

X3-7

X3-27

X3-8

X3-24,25

X3-1,2,3

X3-22,26

X3-28

X3-29

X3-4,23

IDM

X-3

X-1

X-2

CMPO

1 3 5

2 4 6

Glow Plug Circuits

Yellow Red White

P-O

DB-LG

R-Y

LB-PK

BK-W

DB-LG

LB-R

GY-R

BR-W

LG-BK

DB-LG

R-W

LG-R

BR-O

LG-R

P-O

Y-R

W-LG

LG-Y

DB-O

P-OBKR-LG

LB-W

W-R

DB-Y

W-BK

R-W

Position Sensor Shield Drain

G-R

BR-LG

Valve Motor + (U Phase)

Valve Motor + (V Phase)

Valve Motor + (W Phase)

821

Color

Cylinder

CKP

CMP

Cylinder 1

Cylinder 5

Cylinder 3

Cylinder 2

Cylinder 4

Cylinder 6

Injector drain wire ground

2143243

3124312

X1-3

X1-17

X1-8

X1-1

X1-23

X1-6

X1-24

X1-2

X1-19

X1-5

X1-20

X2-2

X2-17

X2-6

X2-18

X2-1

X2-21

X2-5

X2-22

X2-4

X2-19

X2-8

X2-20

X1-18

243

124

Open coil ground

Open coil power

Close coil ground

Close coil power

Open coil ground

Open coil power

Close coil ground

Close coil power

Open coil ground

Open coil power

Close coil ground

Close coil power

Close coil ground

Open coil ground

Open coil power

Close coil power

Open coil ground

Open coil power

Close coil ground

Close coil power

Open coil ground

Open coil power

Close coil ground

Close coil power

T-Y

LG-BK

LG-R

LG-O

LG-Y

O-Y

O-LB

LG-W

Y-LB

W-BK

W-LB

LB-R

W-LB

O-Y

DB-O

DG-LG

O-LG

LB-BK

BK-PK

W-P

DG-P

T-LG

A/C clutch

Alternator

control

Chassis Connections – consult

chassis

/ body manuals

ENGINE & CHASSIS SCHEMATIC

ELECTRONIC CONTROL SYSTEM DIAGNOSTICS

ENGINE MOUNTED

COMPONENTS

VT 275

International

In-line connector

Act Pwr Gnd

IDM MPR

IDM Logic Pwr

IDM Pwr Gnd

ALT I-Sense

ATA (-)

ATA (+)

A/C Clutch (-)

A/C Clutch (+)

IDM Main Pwr

12 Pin connector

IGN

MAF

Signal Ground

REF

MAP

ICP

EOP

MAT

ECT

EOT

CMP (-)

CMP/CKP SHD

CKP (+)

BCS

IPR

GPC

GPD

IAHC

IAHD

CKPO

CAN 2 (+)

CAN 2 (-)

CAN 2 SHD

BOO

BPS

CMPO

BPS

BOO

IPR PWR

Act Pwr

CKP (-)

IAT

75ECM

Chassis

(

white)

X-3

X-4

X1-7

X2-2

X1-6

X1-14

X2-3

X1-13

X1-20

X2-14

X1-8

X2-1

X1-9

X1-10

X1-1

X1-11

X1-2

X2-18

X2-24

X1-12

X1-17

X1-21

X1-18

X2-11

X1-19

X1-24

X2-6

X2-13

X2-12

X1-15

X1-16

ECM

Engine

(

gray)

X-1

X-2

CMP (+)

P-O

DB-LG

R-Y

LB-PK

BK-W

DB-LG

LB-R

GY-R

BR-W

LG-BK

DB-LG

R-W

LG-R

BR-O

LG-R

P-O

Y-R

W-LG

LG-Y

DB-O

P-O

R-Y

R-LG

LB-W

W-R

DB-Y

W-BK

R-W

1 Water In Fuel

V – 7V

V – B+

V = No water, 7V = water in fuel, EST – No/Yes

ECM Switch Ignition voltageB+

V – B+

Switched Ignition power key On

= B+, Key Off = 0V

Engine Coolant Level

V Low – 5V Full

V – 5V

V = Low Coolant 5V = Full Coolant

ECM Main Power Relay Control0.6V – 1V

.6V – 1V/B+

.6V – 1V = MPR On / B+ = MPR Off

Battery Ground

0V0VECM Ground

Battery Ground

0V0VECM Ground

Driveline Disengagement Switch0V – B+

V – B+

Key On

= 0V in gear / B+ = Park and neutral

Fuel Pump control

V Off – B+ On

V – B+

+ = FPC On, 0V = FPC Off, EST – Output State Test

Air Conditioner Demand

0V0

V – 5V

V with A/C switch on, freon switches closed. 0V Off

Tachometer Output

Chassis body builder option only

CAN 1 (Public)

V – 4V

Digital signal communication

CAN 1 (Public)

V – 4V

Digital signal communication

Resume Accel Switch

V Off – B+ On

V – B+

Momentary switch

0V at normal state / B+ depressed

CAN 1 Shield

0V0VGround shield for CAN

Vehicle Speed Signal

Chassis body builder option only

Remote Preset (PTO)

Chassis body builder option only

Remote Variable (PTO)

Chassis body builder option only

Speed Control Switch

V Off – B+ On

Momentary switch

0V at normal state / B+ depressed

Air Conditioner Control

B+0

V Off – B+ On

+ A/C command Off, 0V A/C command On

Engine Crank Inhibit

V / 4V – 5V

V – 4 to 5V

V allows cranking / 4 – 5V inhibits cranking

Barometric Pressure

Alt

. Depend.

V – 5V

DMM set to V

, EST – Continuous Monitor session

X3 CHASSIS CONNECTOR (WHITE

)

X4 CHASSIS CONNECTOR (WHITE

)

1 ECM Power

B+0

V – 5V

ECM B

+ from ECM relay

ECM Power

B+0

V – 5V

ECM B

+ from ECM relay

Voltage Reference B (Chassis)5V ± 0.5

V ± 0.5V

V voltage reference for chassis sensors

Cruise ON / OFF Switch

V Off – B+ On

V Off – B+ ON

Cruise control On

/Off switch

Idle Validation Switch

V Off

V – B+

V at normal state, B+ pedal depressed

Fuel Pump Monitor

V Off – B+ On

V – B+

+ = FPC On, 0V = FPC Off, EST – Output State Test

Warn Engine Lamp

Chassis body builder option only

Accelerator Position Sensor0.7V – 4.2V

V – 5V

.7V = 10% / 4.2V = 102%

Communication Link

.1V – 1.2V

V – 5V

Diagnostic

/ Programming

Communication Link

.0V – 4.2V

V – 5V

Diagnostic

/ Programming

Signal Ground

0V0VGround for chassis sensors

12 PIN CONNECTOR (BLACK)

Operating

Range

Comments

Key ON

Signal

Circuit

ATA (-)

ATA (+)

ECM PWR

Battery Ground

ECM MPR

FPC

WIF

RPRE

RVAR

A/C control

ECI

FPM

TACH

RAS

SCS

COO

AC demand

CAN 1 (+)

CAN 1 (-)

BAP

DDS

IGN

X3-1

X3-19

X3-20

X3-22

X3-23

X4-15

X4-17

X3-11

X3-14

X4-6

X3-21

X3-10

X3-12

X3-13

X3-15

X3-17

X3-9

X3-5

X3-6

X4-2

X4-1

X3-8

X3-3

X3-24

X4-18

X4-24

X3-7

X4-20

X4-21

X4-12

X4-4

WEL

VSS CAL (speedo)

IVS

REF

APS

CAN 1 SHD

Signal Ground

ECL

X3-4

8 BPS

B+0

V – B+

+ at normal state, 0V pedal depressed

BOO

0V0

V – B+

V at normal state, B+ pedal depressed

IN-LINE CONNECTOR

WARNING

Notes

Colored lines on this schematic go to connector terminals

for sensors and actuators

Color code for

schematic lines

Schematic Line

description

Red

12 Volts (VBAT)

Purple

Injectors (48 Volts)

Blue

VREF (5 Volts)

Green

Signal circuit

Brown

Data Communication Link

Black

Ground circuit

Red

Low side driver control

Black

High side driver control

To avoid serious personal injury, possible death or damage

to the engine or vehicle

, read all safety instructions in the

Safety Information" section of

Engine Diagnostics Manual

EGES

-305 before doing diagnostic procedures.

4 9

8 6

1 2 3

7 5

Battery ground Switch Ignition Voltage Actuator Power IDM Main Power Relay Control IDM Logic Power IDM Main Power Battery Ground Communication Link Communication Link Alternator Charge Warning A/C Clutch Relay Battery Ground

0V Off - B+ On

0.1V - 1.2V

0.0V - 4.2V

0.7V - 4.2V 0V Off - B+ On 0V 0V

0.1V - 1.2V

0.0V - 4.2V

0V Off

0V Off - B+ On 0V - 5V 0V - 5V 0V - 5V 0V - B+ 0V 0V 0V - 5V 0V - 5V

0V - B+

Diagnostic / Programming Diagnostic / Programming

0.7V = 10% / 4.2V = 102% B+ = FPC On. 0V = FPC Off, EST - Output State Test Ground for chassis sensors IDM Ground Diagnostic / Programming Diagnostic / Programming Chassis body builder option only Chassis body builder option only 0V at normal state, B+ pedal depressed

GLOSSARY

Accelerator Position Sensor (APS)

A potentiometer sensor that indicates the position of the throttle pedal.

Actuator

A device that performs work in response to an electrical input signal.

Aeration

The entrainment of gass (air or combustion gas) in the coolant or lubricant.

American Trucking Association (ATA) Datalink

A serial datalink speciﬁed by the American Trucking Association and the SAE.

Barometric Absolute Pressure (BAP) Sensor

A variable capacitance sensor which, when supplied with a 5 volt reference signal from the ECM, produces a linear analog voltage signal indicating atmospheric pressure.

Boost Control Solenoid Harness

The hose harness that is used to transfer boost pressure from the intake manifold to the Boost Control Solenoid and the Pneumatic Actuator.

Boost Pressure

The pressure of the charge air leaving the turbocharger.

Camshaft Position (CMP) Sensor

A magnetic pickup sensor that indicates engine speed and camshaft position.

CAN 1

A data link between the vehicle modules and ECM.

CAN 2

The private link between the ECM and IDM.

Catalytic Converter

An antipollution device in the exhaust system that contains a catalyst for chemically converting some pollutants in the exhaust gases (carbon monoxide, unburned hydrocarbons, and oxides of nitrogen) into harmless compounds.

Charge Air

Dense, pressurized, heated air discharged from the turbocharger.

Controller Area Network (CAN)

A J1939 high speed communication link.

Coolant

A ﬂuid used to transport heat from the engine to the radiator.

Crankcase

The housing that encloses the crankshaft, connecting rods, and associated parts.

Crankshaft Position (CKP) Sensor

A magnetic pickup sensor that determines crankshaft position and speed.

Duty Cycle

A control signal that has a controlled on/off time measurement from 0 to 100%. Normally used to control solenoids.

Electronic Control Module (ECM)

An electronic processor that monitors and controls the engine.

EGR Cooler

A cooler that allows heat to dissipate from the exhaust gasses before they enter the EGR Valve.

EGR Valve

A valve that regulates the ﬂow of exhaust gasses into the intake manifold.

Engine Oil Pressure Switch (EOPS)

A switch that senses oil pressure.

Engine Oil Temperature (EOT) Sensor

A thermistor sensor that senses engine oil temperature.

Exhaust Gas Recirculation

A system used to recirculate a portion of the exhaust gases into the intake air charge in order to reduce oxides of nitrogen (NOx).

Injection Control Pressure (ICP)

High lube oil pressure generated by a high pressure pump/pressure regulator used to hydraulically actuate the fuel injectors.

GLOSSARY

Injection Control Pressure (ICP) Sensor

A sensor that measures injection control pressure.

Injection Pressure Regulator (IPR)

An ECM regulated valve that varies injection control pressure.

Injector Drive Module (IDM)

An electronic processor that calculates injection timing and fuel quantity and is the power supply for the injectors.

Intake Air Temperature (IAT) Sensor

A thermistor sensor that senses intake air temperature.

Manifold Absolute Pressure (MAP)

Boost pressure in the manifold that is a result of the turbocharger.

Manifold Absolute Pressure (MAP) Sensor

A variable capacitance sensor that measures boost pressure.

Reference Voltage (VREF)

A 5 volt reference supplied by the ECM to operate the engine sensors.

Thermistor

A semiconductor device that changes resistance as temperature changes.

Turbocharger

A turbine driven compressor mounted to the exhaust manifold. The turbocharger increases the pressure, temperature and density of the intake air.

Manifold Air Temperature (MAT) Sensor

A thermistor style sensor used to indicate air temperature in the intake manifold.

Mass Air Flow (MAF) Sensor

A sensor that measures the air ﬂow into the engine.

Magnehelic Gauge

A gauge that measures pressure in inches of water (in H2O).

Magnetic Pickup Sensor

A sensor that creates an alternating current current voltage when a magnetic ﬁeld is broken.

Oxides of Nitrogen (NOx)

Oxides of nitrogen form by a reaction between nitrogen and oxygen at high temperatures.

Potentiometer

An electro-mechanical device that senses the position of a mechanical component.

International VT-275 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

FORWARD

Safety Information

TABLE OF CONTENTS

SPECIAL TOOLS

POWER DISTRIBUTION CENTER

ENGINE & CHASSIS SCHEMATIC

GLOSSARY