CHRYSLER VOYAGER 2001 Service Manual

NOTES
54

10.0 SCHEMATIC DIAGRAMS
TEVES MARK 20 ANTILOCK BRAKE SYSTEM
S
C
H
E
M
A
T
I
C
D
I
A
G
R
A
M
S
55
SCHEMATIC DIAGRAMS

NOTES
56

TABLE OF CONTENTS
1.0 INTRODUCTION.........................................................1
1.1SYSTEM COVERAGE...............................................1
1.2SIX-STEP TROUBLESHOOTING PROCEDURE..........................1
2.0 IDENTIFICATION OF SYSTEM.............................................1
3.0 SYSTEM DESCRIPTION AND FUNCTIONAL OPERATION......................1
3.1GENERAL DESCRIPTION............................................1
3.2FUNCTIONAL OPERATION...........................................1
3.2.1ECM ON-BOARD DIAGNOSTICS..............................1
3.2.2ECM OPERATING MODES...................................2
3.2.3MONITORED CIRCUITS......................................2
3.2.4SKIS OVERIVEW...........................................2
3.2.5SKIS ON-BOARD DIAGNOSTICS..............................2
3.2.6SKIS OPERATION...........................................2
3.3DIAGNOSTIC TROUBLE CODES......................................3
3.3.1HARD CODE...............................................3
3.3.2INTERMITTENT CODE.......................................3
3.3.3ECM DIAGNOSTIC TROUBLE CODES..........................3
3.3.4SKIM DIAGNOSTIC TROUBLE CODES.........................6
3.3.5HANDLING NO TROUBLE CODE PROBLEMS...................6
3.4USING THE DRBIIIT.................................................6
3.4.1DRBIIITDOES NOT POWER UP...............................6
3.4.2DISPLAY IS NOT VISIBLE....................................6
4.0 DISCLAIMERS, SAFETY, WARNINGS.......................................7
4.1DISCLAIMERS......................................................7
4.2SAFETY...........................................................7
4.2.1TECHNICIAN SAFETY INFORMATION..........................7
4.2.2VEHICLE PREPARATION FOR TESTING........................7
4.2.3SERVICING SUB-ASSEMBLIES...............................7
4.2.4DRBIIITSAFETY INFORMATION...............................7
4.3WARNINGS AND CAUTIONS.........................................8
4.3.1ROAD TEST WARNINGS.....................................8
4.3.2VEHICLE DAMAGE CAUTIONS...............................8
5.0 REQUIRED TOOLS AND EQUIPMENT......................................8
6.0 GLOSSARY OF TERMS...................................................8
7.0 DIAGNOSTIC INFORMATION AND PROCEDURES............................9
COMMUNICATION
*NO RESPONSE FROM ECM (PCI BUS) - DIESEL ONLY......................10
*NO RESPONSE FROM ECM (SCI ONLY) - DIESEL ONLY.....................11
DRIVEABILITY - DIESEL
P0100-MASS AIR FLOW SENSOR PLAUSIBILITY............................13
P0100-MASS AIR FLOW SENSOR PLAUSIBILITY POSITIVE AREA..............13
P0100-MASS AIR FLOW SENSOR SIGNAL VOLTAGE TOO HIGH...............13
P0100-MASS AIR FLOW SENSOR SIGNAL VOLTAGE TOO LOW...............13
i

TABLE OF CONTENTS - Continued
P0100-MASS AIR FLOW SENSOR SUPPLY VOLTAGE TOO HIGH OR LOW......13
P0105-BAROMETRIC PRESSURE CIRCUIT SIGNAL VOLTAGE TOO HIGH.......20
P0105-BAROMETRIC PRESSURE CIRCUIT SIGNAL VOLTAGE TOO LOW........20
P0606-ECM ERROR GATE ARRAY - COMMUNICATION.......................20
P0606-ECM ERROR GATE ARRAY - COMMUNICATION NOT VERIFIED..........20
P0606-ECM ERROR GATE ARRAY - QUANTITY STOP........................20
P0606-ECM ERROR RECOVERY HAS OCCURRED..........................20
P0606-ECM ERROR REDUNDANT OVERRUN MONITORING..................20
P1206-CALCULATED INJECTOR VOLTAGE TOO HIGH........................20
P1206-CALCULATED INJECTOR VOLTAGE TOO LOW........................20
P1601-CAPACITOR VOLTAGE 1 VOLTAGE TOO HIGH........................20
P1601-CAPACITOR VOLTAGE 1 VOLTAGE TOO LOW.........................20
P1606-AFTER RUN SHUT OFF ERROR-INJECTION POWERSTAGE............20
P1606-AFTER RUN SHUT OFF ERROR-ZERO QUANTITY.....................20
P1610-VOLTAGE REGULATOR SIGNAL VOLTAGE TOO HIGH..................20
P1610-VOLTAGE REGULATOR SIGNAL VOLTAGE TOO LOW..................20
P1680-EEPROM PLAUSIBILITY CHECKSUM ERROR.........................20
P1680-EEPROM PLAUSIBILITY CODE WORD INCORRECT OR MISSING........20
P1680-EEPROM PLAUSIBILITY COMMUNICATION ERROR....................20
P1680-EEPROM PLAUSIBILITY VARIATION NUMBER ERROR.................20
P1680-EEPROM PLAUSIBILITY VIN CHECKSUM ERROR.....................20
P1680-EEPROM PLAUSIBILITY WRITE ERROR..............................20
P1696-EEPROM MEMORY WRITE DENIED.................................20
P0110-INTAKE AIR TEMP SENSOR CIRCUIT SIGNAL VOLTAGE TOO HIGH......24
P0110-INTAKE AIR TEMP SENSOR CIRCUIT SIGNAL VOLTAGE TOO LOW.......27
P0115-ENGINE COOLANT TEMP SENSOR CIRCUIT SIGNAL
VOLTAGE TOO HIGH....................................................29
P0115-ENGINE COOLANT TEMP SENSOR CIRCUIT SIGNAL
VOLTAGETOO LOW ....................................................32
P0190-FUEL PRESS SENSOR CIRCUIT MALF SIGNAL VOLTAGE TOO HIGH.....34
P0190-FUEL PRESS SENSOR CIRCUIT MALF SIGNAL VOLTAGE TOO LOW.....38
P0190-FUEL PRESS SENSOR CIRCUIT MALF SUPPLY VOLTAGE
TOO HIGH OR LOW.....................................................40
P0195-OIL TEMP SENSOR CIRCUIT MALF SIGNAL VOLTAGE TOO HIGH........41
P0195-OIL TEMP SENSOR CIRCUIT MALF SIGNAL VOLTAGE TOO LOW........44
P0201-CYLINDER 1-INJECTOR CIRCUIT CURRENT DECREASE...............46
P0201-CYLINDER 1-INJECTOR CIRCUIT LOAD DROP........................46
P0201-CYLINDER 1-INJECTOR CIRCUIT OVERCURRENT HIGH SIDE...........46
P0201-CYLINDER 1-INJECTOR CIRCUIT OVERCURRENT LOW SIDE...........46
P0202-CYLINDER 2-INJECTOR CIRCUIT CURRENT DECREASE...............50
P0202-CYLINDER 2-INJECTOR CIRCUIT LOAD DROP........................50
P0202-CYLINDER 2-INJECTOR CIRCUIT OVERCURRENT HIGH SIDE...........50
P0202-CYLINDER 2-INJECTOR CIRCUIT OVERCURRENT LOW SIDE...........50
P0203-CYLINDER 3-INJECTOR CIRCUIT CURRENT DECREASE...............54
P0203-CYLINDER 3-INJECTOR CIRCUIT LOAD DROP........................54
P0203-CYLINDER 3-INJECTOR CIRCUIT OVERCURRENT HIGH SIDE...........54
P0203-CYLINDER 3-INJECTOR CIRCUIT OVERCURRENT LOW SIDE...........54
P0204-CYLINDER 4-INJECTOR CIRCUIT CURRENT DECREASE...............58
P0204-CYLINDER 4-INJECTOR CIRCUIT LOAD DROP........................58
P0204-CYLINDER 4-INJECTOR CIRCUIT OVERCURRENT HIGH SIDE...........58
P0204-CYLINDER 4-INJECTOR CIRCUIT OVERCURRENT LOW SIDE...........58
P0235-BOOST PRESSURE SENSOR PLAUSIBILITY..........................62
P0235-BOOST PRESSURE SENSOR SIGNAL VOLTAGE TOO HIGH.............64
ii

TABLE OF CONTENTS - Continued
P0235-BOOST PRESSURE SENSOR SIGNAL VOLTAGE TOO LOW.............67
P0235-BOOST PRESSURE SENSOR SUPPLY VOLTAGE TOO HIGH OR LOW....70
P0335-CKP POSITION SENSOR CIRCUIT OVERSPEED RECOGNITION.........73
P0340-CKP POSITION SENSOR CIRCUIT DYNAMIC PLAUSIBILITY.............75
P0340-CMP POSITION SENSOR CIRCUIT CMP/CKP SYNC FAILURE...........77
P0340-CMP POSITION SENSOR CIRCUIT SIGNAL FREQUENCY TOO HIGH.....80
P0340-CMP POSITION SENSOR CIRCUIT STATIC PLAUSIBILITY...............80
P0380-GLOW PLUG CIRCUIT A OPEN CIRCUIT.............................84
P0380-GLOW PLUG CIRCUIT A SHORT CIRCUIT............................84
P0403-EGR SOLENOID CIRCUIT OPEN CIRCUIT............................87
P0403-EGR SOLENOID CIRCUIT SHORT CIRCUIT...........................90
P0480-FAN 1 CONTROL CIRCUIT OPEN CIRCUIT...........................92
P0480-FAN 1 CONTROL CIRCUIT SHORT CIRCUIT..........................94
P0481-FAN 2 CONTROL CIRCUIT OPEN CIRCUIT...........................96
P0481-FAN 2 CONTROL CIRCUIT SHORT CIRCUIT..........................98
P0500-VEHICLE SPEED SENSOR FREQUENCY TOO HIGH..................100
P0500-VEHICLE SPEED SENSOR HIGH LEVEL DURATION...................100
P0500-VEHICLE SPEED SENSOR PLAUSIBILITY...........................100
P0500-VEHICLE SPEED SENSOR SIGNAL VOLTAGE TOO HIGH..............100
P0514-BATTERY TEMP SENSOR CIRCUIT SIGNAL VOLTAGE TOO HIGH.......104
P0520- OIL PRESS SENSOR CIRCUIT MALF PLAUSIBILITY..................107
P0520-OIL PRESS SENSOR CKT MALF SUPPLY VOLTAGE TOO HIGH OR LOW .110
P0530-A/C PRESSURE SENSOR CIRCUIT PLAUSIBILITY....................112
P0530-A/C PRESSURE SENSOR CIRCUIT SIGNAL VOLTAGE TOO HIGH.......112
P0530-A/C PRESSURE SENSOR CIRCUIT SIGNAL VOLTAGE TOO LOW.......112
P0530-A/C PRESSURE SENSOR CIRCUIT SUPPLY VOLTAGE TOO HIGH OR
LOW.................................................................112
P0560-SYSTEM VOLTAGE TOO HIGH.....................................117
P0560-SYSTEM VOLTAGE TOO LOW.....................................120
*CHECKING THE CHARGING SYSTEM OPERATION - DIESEL................120
P0615-STARTER RELAY CIRCUIT SHORT CIRCUIT.........................124
P0620-GENERATOR FIELD CONTROL MALF BATTERY VOLTAGE
DEVIATION TOO HIGH.................................................126
P0620-GENERATOR FIELD CONTROL MALF BATTERY VOLTAGE
DEVIATION TOO LOW..................................................126
P0620-GENERATOR FIELD CONTROL MALF BATTERY VOLTAGE TOO HIGH . . .126
P0620-GENERATOR FIELD CONTROL MALF BATTERY VOLTAGE TOO LOW. . . .126
P0620-GENERATOR FIELD CONTROL MALF CHARGING VOLTS TOO LOW. . . .126
P0620-GENERATOR FIELD CONTROL MALF OPEN CIRCUIT.................126
P0620-GENERATOR FIELD CONTROL MALF SHORT CIRCUIT................126
P0620-GENERATOR FIELD CONTROL MALF UNSTABLE CURRENT...........126
P0627-FUEL LIFT PUMP RELAY CONTROL CIRCUIT OPEN CIRCUIT..........129
P0627-FUEL LIFT PUMP RELAY CONTROL CIRCUIT SHORT CIRCUIT.........131
P0641-SENSOR REFERENCE VOLTAGE A CKT VOLTAGE TOO HIGH..........133
P0651-SENSOR REFERENCE VOLTAGE B CKT VOLTAGE TOO HIGH..........133
P0641-SENSOR REFERENCE VOLTAGE A CKT VOLTAGE TOO LOW..........136
P0651-SENSOR REFERENCE VOLTAGE B CKT VOLTAGE TOO LOW..........136
P0645-A/C CLUTCH RELAY CIRCUIT OPEN CIRCUIT........................139
P0645-A/C CLUTCH RELAY CIRCUIT SHORT CIRCUIT......................142
P0685-ECM/PCM RELAY CONTROL CIRCUIT SHUTS OFF TOO EARLY........145
P0685-ECM/PCM RELAY CONTROL CIRCUIT SHUTS OFF TOO LATE..........147
P0703-BRAKE SWITCH SIGNAL CIRCUITS PLAUSIBILITY WITH
REDUNDANT CONTACT................................................149
iii

TABLE OF CONTENTS - Continued
P0703-BRAKE SWITCH SIGNAL CKTS PLAUS W/REDUNDANT CONTACT
AFTER INITIALIZATION.................................................149
P0833-CLUTCH PEDAL PLAUSIBILITY....................................153
P1130-FUEL RAIL PRESSURE MALFUNCTION LEAKAGE DETECTED..........155
P1130-FUEL RAIL PRESSURE MALFUNCTION PRESSURE TOO HIGH-SHUT
OFF .................................................................155
P1130-FUEL RAIL PRESSURE MALFUNCTION PRESSURE TOO LOW.........155
P1130-FUEL RAIL PRESSURE MALFUNCTION SOLENOID OPEN.............155
P1131-FUEL PRESSURE SOLENOID OPEN CIRCUIT........................158
P1131-FUEL PRESSURE SOLENOID PLAUSIBILITY IN AFTER-RUN............158
P1131-FUEL PRESSURE SOLENOID SHORT CIRCUIT.......................158
P1511-BATTERY SENSE LINE 1 VOLTAGE TOO HIGH.......................162
P1511-BATTERY SENSE LINE 1 VOLTAGE TOO LOW.......................164
P1605-IGNITION SWITCH PLAUSIBILITY..................................166
P1685-SKIM SYSTEM INVALID KEY CODE RECEIVED.......................168
P1685-SKIM SYSTEM INVALID SECRET KEY IN EEPROM....................168
P1685-SKIM SYSTEM KEY COMMUNICATION TIMED OUT...................168
P1685-SKIM SYSTEM SKIM ERROR......................................168
P1685-SKIM SYSTEM WRITE ACCESS TO EEPROM FAILURE................168
P2120-ACC PEDAL POSITION SENSOR 1 CKT PLAUSIBILITY................170
P2120-ACC PEDAL POSITION SENSOR 1 CKT PLAUSIBILITY WITH BRAKE
SWITCH..............................................................170
P2120-ACC PEDAL POSITION SENSOR 1 CKT PLAUSIBILITY WITH
POTENTIOMETER.....................................................170
P2120-ACC PEDAL POSITION SENSOR 1 CKT SIGNAL VOLTAGE TOO HIGH . . .170
P2120-ACC PEDAL POSITION SENSOR 1 CKT SIGNAL VOLTAGE TOO LOW . . .170
P2120-ACC PEDAL POSITION SENSOR 1 CKT SUPPLY VOLTAGE TOO
HIGH OR LOW........................................................170
*CHECKING THE A/C CLUTCH OPERATION...............................179
*CHECKING THE ACCELERATOR PEDAL POSITION SENSOR CALIBRATION . . .181
*CHECKING THE BOOST PRESSURE SENSOR CALIBRATION................182
*CHECKING THE ECM POWER AND GROUND CIRCUITS....................183
*CHECKING THE EGR SYSTEM..........................................185
*CHECKING THE ELECTRIC RADIATOR FAN OPERATION...................186
*CHECKING THE ENGINE COOLANT TEMPERATURE SENSOR CALIBRATION . .193
*CHECKING THE ENGINE MECHANICAL SYSTEMS.........................194
*CHECKING THE GLOW PLUG OPERATION...............................195
*CHECKING THE LIFT PUMP MOTOR OPERATION.........................197
*CHECKING THE MAF SENSOR CALIBRATION.............................200
*CHECKING THE SPEED CONTROL OPERATION...........................201
*CHECKING THE VEHICLE SPEED SIGNAL................................204
*ENGINE CRANKS BUT WILL NOT START.................................207
*ENGINE WILL NOT CRANK.............................................210
VEHICLE THEFT/SECURITY
ANTENNA FAILURE....................................................214
COP FAILURE.........................................................214
EEPROM FAILURE.....................................................214
INTERNAL FAULT......................................................214
RAM FAILURE.........................................................214
SERIAL LINK INTERNAL FAULT..........................................214
STACK OVERFLOW FAILURE............................................214
PCM STATUS FAILURE.................................................216
iv

TABLE OF CONTENTS - Continued
SERIAL LINK EXTERNAL FAULT.........................................216
ROLLING CODE FAILURE...............................................218
VIN MISMATCH........................................................218
TRANSPONDER COMMUNICATION FAILURE..............................220
TRANSPONDER CYCLIC REDUNDANCY CHECK (CRC) FAILURE.............220
TRANSPONDER ID MISMATCH..........................................220
TRANSPONDER RESPONSE MISMATCH..................................220
VERIFICATION TESTS
VERIFICATION TESTS..................................................223
8.0 COMPONENT LOCATIONS..............................................227
8.1CONTROL MODULES.............................................227
8.2CONTROLS AND SOLENOIDS......................................227
8.3DATA LINK CONNECTOR..........................................227
8.4FUEL SYSTEM...................................................228
8.5RELAYS.........................................................228
8.6SENSORS.......................................................229
8.7SWITCHES......................................................230
9.0 CONNECTOR PINOUTS................................................231
A/C COMPRESSOR CLUTCH - LT. GRAY 2 WAY............................231
A/C PRESSURE SENSOR - GRAY 4 WAY..................................231
ACCELERATOR PEDAL POSITION SENSOR (DIESEL) - BLACK 10 WAY........231
BATTERY TEMPERATURE SENSOR (DIESEL) - BLACK 2 WAY................231
BOOST PRESSURE SENSOR (DIESEL) - BLACK 4 WAY.....................232
BRAKE LAMP SWITCH - BLACK 6 WAY...................................232
CAMSHAFT POSITION SENSOR (DIESEL) - BLACK 3 WAY...................232
CLUTCH PEDAL UPSTOP SWITCH (DIESEL) - RED 2 WAY...................232
CRANKSHAFT POSITION SENSOR (DIESEL) - BLACK 3 WAY................232
DATA LINK CONNECTOR - BLACK 16 WAY................................233
EGR SOLENOID (DIESEL) - LT. GRAY 2 WAY...............................233
ENGINE CONTROL MODULE C1 (DIESEL) - BLACK 81 WAY..................234
ENGINE CONTROL MODULE C1 (DIESEL) - BLACK 81 WAY..................235
ENGINE CONTROL MODULE C2 (DIESEL) - BLACK 40 WAY..................236
ENGINE COOLANT TEMP SENSOR (DIESEL) - BLUE 2 WAY.................236
ENGINE OIL PRESSURE SENSOR (DIESEL) - BLACK 3 WAY.................237
ENGINE OIL TEMPERATURE SENSOR (DIESEL) - BLACK 2 WAY.............237
FUEL HEATER (DIESEL) - BLACK 2 WAY..................................237
FUEL INJECTOR NO. 1 (DIESEL) - BLACK 2 WAY...........................237
FUEL INJECTOR NO. 2 (DIESEL) - BLACK 2 WAY...........................237
FUEL INJECTOR NO. 3 (DIESEL) - BLACK 2 WAY...........................238
FUEL INJECTOR NO. 4 (DIESEL) - BLACK 2 WAY...........................238
FUEL PRESSURE SENSOR (DIESEL) - BLACK 3 WAY.......................238
FUEL PRESSURE SOLENOID (DIESEL) - BLACK 2 WAY.....................238
GENERATOR - BLACK 2 WAY...........................................238
GLOW PLUG RELAY (DIESEL) - BLACK 4 WAY.............................239
INTELLIGENT POWER MODULE C3 (DIESEL) - YELLOW/RED 20 WAY.........239
LEFT SPEED CONTROL SWITCH - WHITE 2 WAY..........................239
LIFT PUMP MOTOR (DIESEL) - BLACK 2 WAY..............................239
MASS AIR FLOW SENSOR (DIESEL) - ORANGE 5 WAY......................240
v

TABLE OF CONTENTS - Continued
A/C COMPRESSOR CLUTCH RELAY......................................242
ECM/PCM RELAY (DIESEL).............................................242
FUEL HEATER RELAY (DIESEL)..........................................242
LIFT PUMP RELAY (DIESEL).............................................242
STARTER MOTOR RELAY...............................................242
RADIATOR FAN NO. 1 (DIESEL) - GRAY 2 WAY.............................242
RADIATOR FAN NO. 2 (DIESEL) - GRAY 2 WAY.............................243
RADIATOR FAN RELAY NO. 1 (DIESEL) - BLUE 9 WAY......................243
RADIATOR FAN RELAY NO. 2 (DIESEL) - BLUE 9 WAY......................243
RADIATOR FAN RELAY NO. 3 (DIESEL) - BLUE 9 WAY......................243
RIGHT SPEED CONTROL SWITCH - WHITE 2 WAY.........................244
SENTRY KEY IMMOBILIZER MODULE - BLACK 6 WAY......................244
VEHICLE SPEED SENSOR (MTX/ATX) - BLACK 3 WAY......................244
WATER IN FUEL SENSOR (DIESEL) - BLACK 2 WAY........................244
10.0 SCHEMATIC DIAGRAMS................................................245
10.12001 RG 2.5L TURBO DIESEL......................................245
11.0 CHARTS AND GRAPHS................................................247
vi

1.0 INTRODUCTION
The procedures contained in this manual include
all the specifications, instructions and graphics
needed to diagnose engine control module (ECM)
and sentry key immobilizer system (SKIS) prob-
lems; they are no start, diagnostic trouble code
(DTC), and no trouble code problems for the ECM.
The diagnostics in this manual are based on the
trouble condition or symptom being present at the
time of diagnosis.
When repairs are required, refer to the appropri-
ate service information for the proper removal and
repair procedure.
Diagnostic procedures change every year. New
diagnostic systems may be added; carryover sys-
tems may be enhanced. IT IS RECOMMENDED
THAT YOU REVIEW THE ENTIRE MANUAL TO
BECOME FAMILIAR WITH ALL NEW AND
CHANGED DIAGNOSTIC PROCEDURES.
This manual is designed to begin all diagnosis at
the DTC TEST, which is located at the beginning of
Section 7.0. This will cover all the necessary re-
quirements to begin a logical diagnostic path for
each problem. If there is a diagnostic trouble code
(DTC) detected, it will direct you to the trouble code
test. If there are no DTCs present, it will direct you
by symptom to a no trouble code test.
This book reflects many suggested changes from
readers of past issues. After using this book, if you
have any comments or recommendations, please fill
out the form at the back of the book and mail it back
to us.
1.1 SYSTEM COVERAGE
This diagnostic procedures manual covers all
2001 RG body vehicles equipped with the 2.5L VM
diesel engine.
1.2 SIX-STEP TROUBLESHOOTING
PROCEDURE
Diagnosis of the engine control module (ECM)
and sentry key immobilizer system (SKIS) is done
in six basic steps:
²verification of complaint
²verification of any related symptom
²symptom analysis
²problem isolation
²repair of isolated problem
²verification of proper operation
NOTE: All tests in this manual should be per-
formed with the engine at operating temperature,
unless specified within a particular test.
2.0 IDENTIFICATION OF
SYSTEM
The ECM is located in the left side of the engine
compartment between the left front headlamp and
the intelligent power module. The sentry key immo-
bilizer module (SKIM) is located below the steering
column behind the steering wheel.
3.0 SYSTEM DESCRIPTION AND
FUNCTIONAL OPERATION
3.1 GENERAL DESCRIPTION
The 2.5L VM diesel engine system is equipped
with the latest in technical advances. The on-board
diagnostics incorporated in the engine control mod-
ule and SKIM are intended to assist the field
technician in repairing vehicle problems by the
quickest means.
The engine system incorporates a common rail
fuel delivery design. This design utilizes electroni-
cally controlled solenoid valve type fuel injectors.
Each injector is controlled individually by the ECM.
Injector timing and fuel quantity are controlled by
the ECM based on inputs from the various sensors.
The precision control of the injectors by the ECM
helps to reduce the engine noise, odor and smoke.
3.2 FUNCTIONAL OPERATION
3.2.1 ECM ON-BOARD DIAGNOSTICS
The ECM has been programmed to monitor many
different circuits of the diesel fuel injection system.
This monitoring is called on-board diagnostics.
Certain criteria must be met for a trouble code to
be entered into the ECM memory. The criteria may
be a range of: engine rpm, engine temperature, time
or other input signals to the ECM. If all of the
criteria for monitoring a system or circuit are met,
and a problem is sensed, then a DTC will be stored
in the ECM memory.
It is possible that a DTC for a monitored circuit
may not be entered into the ECM memory, even
though a malfunction has occurred. This may hap-
pen when the monitoring criteria has not been met.
The ECM compares input signal voltages from
each input device with specifications (the estab-
lished high and low limits of the input range) that
are programmed into it for that device. If the input
voltage is not within the specifications and other
trouble code criteria are met, a DTC will be stored
in the ECM memory.
1
GENERAL INFORMATION