2000 CHRYSLER VOYAGER ignition

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
3.2FUNCTION OPERATION.............................................1
3.2.1FUEL CONTROL.............................................1
3.2.2ON-BOARD DIAGNOSTICS....................................2
3.2.3OTHER CONTROLS..........................................4
3.2.4PCM OPERATING MODES....................................4
3.2.5NON-MONITORED CIRCUITS..................................5
3.2.6SKIS OVERVIEW............................................5
3.2.7SKIM ON-BOARD DIAGNOSTICS...............................5
3.2.8SKIS OPERATION............................................6
3.2.9PROGRAMMING THE POWERTRAIN CONTROL MODULE..........6
3.2.10PROGRAMMING THE SENTRY KEY IMMOBILIZER MODULE.......7
3.2.11PROGRAMMING THE IGNITION KEYS TO THE SENTRY KEY
IMMOBILIZER MODULE.......................................7
3.3DIAGNOSTIC TROUBLE CODES......................................7
3.3.1HARD CODE................................................7
3.3.2INTERMITTENT CODE........................................8
3.3.3RESET COUNTER...........................................8
3.3.4HANDLING NO TROUBLE CODE PROBLEMS....................8
3.4USING THE DRBIIIT................................................11
3.5DRB ERROR MESSAGES AND BLANK SCREEN........................11
3.5.1DRB IIITDOES NOT POWER UP..............................11
3.5.2DISPLAY IS NOT VISIBLE....................................11
4.0 DISCLAIMERS, SAFETY, WARNINGS......................................11
4.1DISCLAIMERS.....................................................11
4.2SAFETY..........................................................11
4.2.1TECHNICIAN SAFETY INFORMATION..........................11
4.2.2VEHICLE PREPARATION FOR TESTING........................12
4.2.3SERVICING SUB-ASSEMBLIES...............................12
4.2.4DRBIIITSAFETY INFORMATION...............................12
4.3WARNINGS AND CAUTIONS........................................12
4.3.1ROAD TEST WARNINGS.....................................12
4.3.2VEHICLE DAMAGE CAUTIONS...............................12
4.3.3ELECTRONIC PINION FACTOR WARNING......................13
5.0 RECOMMENDED TOOLS AND EQUIPMENT................................13
6.0 GLOSSARY OF TERMS..................................................13
7.0 DIAGNOSTIC INFORMATION AND PROCEDURES...........................15
CHARGING
P-0622 GENERATOR FIELD NOT SWITCHING PROPERLY....................16
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TABLE OF CONTENTS - Continued
P-1492 BATTERY TEMP SENSOR VOLTAGE TOO HIGH......................18
P-1493 BATTERY TEMP SENSOR VOLTAGE TOO LOW.......................18
P-1594 CHARGING SYSTEM VOLTAGE TOO HIGH...........................19
P-1682 CHARGING SYSTEM VOLTAGE TOO LOW...........................21
* CHECKING CHARGING SYSTEM OPERATION WITH NO DTC'S..............24
DRIVEABILITY
P-0106 BAROMETRIC PRESSURE OUT OF RANGE..........................27
P-0107 MAP SENSOR VOLTAGE TOO LOW.................................30
P-0108 MAP SENSOR VOLTAGE TOO HIGH................................32
P-0112 INTAKE AIR TEMP SENSOR VOLTAGE LOW..........................34
P-0113 INTAKE AIR TEMPERATURE SENSOR VOLT HIGH....................36
P-0117 ECT SENSOR VOLTAGE TOO LOW.................................38
P-0118 ECT SENSOR VOLTAGE TOO HIGH.................................40
P-0121 TPS VOLTAGE DOES NOT AGREE WITH MAP........................42
P-0122 THROTTLE POSITION SENSOR VOLTAGE LOW......................45
P-0123 THROTTLE POSITION SENSOR VOLTAGE HIGH......................48
P-0125 CLOSED LOOP TEMP NOT REACHED...............................51
P-0131 1/1 O2 SENSOR VOLTAGE SHORTED TO GROUND...................53
P-0132 1/1 O2 SENSOR SHORTED TO VOLTAGE............................55
P-0133 1/1 O2S SLOW RESPONSE........................................57
P-0134 1/1 O2 SENSOR STAYS AT CENTER................................60
P-0135 O2S HEATER FAILURE............................................62
P-0137 1/2 O2 SENSOR VOLTAGE SHORTED TO GROUND...................64
P-0138 1/2 O2 SENSOR SHORTED TO VOLTAGE............................66
P-0139 1/2 O2S SLOW RESPONSE........................................68
P-0140 1/2 O2 SENSOR STAYS AT CENTER................................71
P-0141 1/2 O2S HEATER FAILURE........................................73
P-0171±1/1 FUEL SYSTEM LEAN..........................................75
P-0201 INJECTOR #1 CONTROL CIRCUIT..................................83
P-0202 INJECTOR #2 CONTROL CIRCUIT..................................86
P-0203 INJECTOR #3 CONTROL CIRCUIT..................................89
P-0204 INJECTOR #4 CONTROL CIRCUIT..................................92
P-0205 INJECTOR #5 CONTROL CIRCUIT..................................95
P-0206 INJECTOR #6 CONTROL CIRCUIT..................................97
P-0300 MULTIPLE CYLINDER MIS-FIRE...................................100
P-0301 CYLINDER #1 MIS-FIRE..........................................100
P-0302 CYLINDER #2 MIS-FIRE..........................................100
P-0303 CYLINDER #3 MIS-FIRE..........................................100
P-0304 CYLINDER #4 MIS-FIRE..........................................100
P-0305 CYLINDER #5 MIS-FIRE..........................................104
P-0306 CYLINDER #6 MIS-FIRE..........................................104
P-0320 NO CRANK REFERENCE SIGNAL AT PCM..........................108
P-0340 NO CAM SIGNAL AT PCM........................................113
P-0351 IGNITION COIL #1 PRIMARY CIRCUIT..............................122
P-0352 IGNITION COIL #2 PRIMARY CIRCUIT..............................125
P-0353 IGNITION COIL #3 PRIMARY CIRCUIT..............................128
P-0401 EGR SYSTEM FAILURE..........................................131
P-0403 EGR SOLENOID CIRCUIT........................................133
P-0420 1/1 CATALYTIC CONVERTER EFFICIENCY..........................136
P-0441 EVAP PURGE FLOW MONITOR FAILURE...........................138
P-0442 EVAP LEAK MONITOR SMALL LEAK DETECTED.....................140
P-0455 EVAP LEAK MONITOR LARGE LEAK DETECTED.....................140
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TABLE OF CONTENTS - Continued
P-0443 EVAP PURGE SOLENOID CIRCUIT................................143
P-0460 FUEL LEVEL UNIT NO CHANGE OVER MILES.......................148
P-0462 FUEL LEVEL SENDING UNIT VOLTS TOO LOW......................149
P-0463 FUEL LEVEL SENDING UNIT VOLTS TOO HIGH......................151
P-0500 NO VEHICLE SPEED SENSOR SIGNAL.............................153
P-0505 IDLE AIR CONTROL MOTOR CIRCUITS.............................159
P-0505B IDLE AIR CONTROL MOTOR CIRCUIT.............................164
P-0505C IDLE AIR CONTROL MOTOR CIRCUIT.............................165
P-0505D IDLE AIR CONTROL MOTOR CIRCUIT.............................166
P-0505E IDLE AIR CONTROL MOTOR CIRCUIT.............................167
P-0600 PCM FAILURE SPI COMMUNICATIONS.............................168
P-0601 INTERNAL CONTROLLER FAILURE................................169
P-0645 A/C CLUTCH RELAY CIRCUIT.....................................170
P-0703 BRAKE SWITCH STUCK PRESSED OR RELEASED..................172
P-1195 SLOW 1/1 O2S DURING CATALYST MONITOR.......................175
P-1281 ENGINE IS COLD TOO LONG.....................................177
P1282 FUEL PUMP RELAY CONTROL CIRCUIT.............................178
P-1294 TARGET IDLE NOT REACHED....................................180
P-1297 NO CHANGE IN MAP FROM START TO RUN........................183
P-1388 AUTO SHUTDOWN RELAY CONTROL CIRCUIT......................186
P-1389 NO ASD RELAY OUTPUT VOLTAGE AT PCM........................188
P-1391 INTERMITTENT LOSS OF CMP OR CKP............................191
P-1398 MISFIRE ADAPTIVE NUMERATOR AT LIMIT.........................198
P-1486 EVAP LEAK MONITOR PINCHED HOSE FOUND.....................200
P-1491 RADIATOR FAN CONTROL RELAY CIRCUIT.........................203
P-1494 LEAK DETECTION PUMP PRESSURE SWITCH......................206
P-1495 LEAK DETECTION PUMP SOLENOID CIRCUIT.......................209
P-1496 5 VOLT SUPPLY OUTPUT TOO LOW...............................212
P-1598 A/C PRESSURE SENSOR VOLTS TOO HIGH........................214
P-1599 A/C PRESSURE SENSOR VOLTS TOO LOW.........................217
P-1695 NO CCD MESSAGE FROM BODY CONTROLLER....................220
P-1696 PCM FAILURE EEPROM WRITE DENIED...........................222
P-1697 PCM FAILURE SRI MILE NOT STORED.............................222
P-1698 NO CCD MESSAGES FROM TCM..................................224
CHECKING 5 VOLT SUPPLY CIRCUIT.....................................226
* CHECKING EGR SYSTEM.............................................228
* CHECKING ENGINE VACUUM..........................................231
* CHECKING EVAPORATIVE EMISSION SYSTEM...........................232
* CHECKING FOR OXYGEN SENSOR SWITCHING..........................234
* CHECKING FUEL DELIVERY...........................................237
* CHECKING IDLE AIR CONTROL MOTOR.................................242
* CHECKING INTAKE AIR TEMPERATURE SENSOR.........................244
* CHECKING MAP SENSOR CALIBRATION................................245
* CHECKING MINIMUM IDLE AIR FLOW...................................246
* CHECKING OXYGEN SENSOR HEATER.................................247
* CHECKING PARK/NEUTRAL POSITION SWITCH..........................249
* CHECKING PCM POWER AND GROUND CIRCUITS.......................251
* CHECKING SECONDARY IGNITION.....................................252
* CHECKING THE ENGINE MECHANICAL SYSTEMS........................253
* CHECKING THROTTLE POSITION SENSOR CALIBRATION.................254
* CHECKING THE A/C PRESSURE SENSOR SIGNAL........................255
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TABLE OF CONTENTS - Continued
SPEED CONTROL
P-1595 SPEED CONTROL SOLENOID CIRCUITS...........................256
P-1683 SPEED CONTROL POWER RELAY OR S/C 12V DRIVER..............256
SPEED CONTROL BRAKE SWITCH OUTPUT..............................261
SPEED CONTROL DENIED MESSAGE....................................263
SPEED CONTROL ON/OFF SWITCH......................................264
* CHECKING SPEED CONTROL OPERATION..............................266
STARTING
*9NO RESPONSE9CONDITION..........................................272
* CHECKING THE CAM AND CRANK SENSORS............................276
* CHECKING THE ENGINE MECHANICAL SYSTEMS........................277
* CHECKING THE FUEL SYSTEM........................................278
* CHECKING THE IDLE AIR CONTROL MOTOR.............................287
* CHECKING THE SECONDARY IGNITION SYSTEM.........................288
* NO CRANK CONDITION...............................................296
* START AND STALL CONDITION.........................................301
TRANSMISSION
P-0740 TORQUE CONV CLUTCH, NO RPM DROP AT LOCKUP...............302
P-0743 TORQUE CONVERTER CLUTCH SOLENOID CIRCUIT................304
P-1899 PARK/NEUTRAL SWITCH STUCK IN PARK OR IN GEAR..............307
ANTENNA FAILURE....................................................310
COP FAILURE.........................................................310
EEPROM FAILURE.....................................................310
INTERNAL FAULTS.....................................................310
RAM FAILURE.........................................................310
SERIAL LINK INTERNAL................................................310
STACK OVERFLOW FAILURE............................................310
SENTRY KEY IMMOBILIZER SYSTEM
PCM STATUS FAILURE.................................................311
ROLLING CODE FAILURE...............................................311
SERIAL LINK EXTERNAL FAULT..........................................311
TRANSPONDER COMMUNICATION FAILURE..............................313
TRANSPONDER ID MISMATCH..........................................313
TRANSPONDER RESPONSE MISMATCH..................................313
VIN MISMATCH........................................................315
VERIFICATION TESTS
VERIFICATION TESTS..................................................317
8.0 COMPONENT LOCATIONS..............................................323
8.1CONTROL MODULES AND PDC.....................................323
8.2CONTROLS & SOLENOIDS.........................................323
8.3DATA LINK CONNECTOR..........................................327
8.4SENSORS.......................................................327
8.5FUEL SYSTEM...................................................330
8.6SWITCHES......................................................331
8.7SPECIFICATIONS.................................................332
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TABLE OF CONTENTS - Continued
9.0 CONNECTOR PINOUTS................................................333
A/C COMPRESSOR CLUTCH - BLACK 2 WAY..............................333
AMBIENT TEMPERATURE SENSOR - GRAY 2 WAY.........................333
AMBIENT TEMPERATURE SENSOR (SENSOR SIDE) 2 WAY..................333
BRAKE LAMP SWITCH - GRAY 6 WAY....................................333
BRAKE SHIFT INTERLOCK SOLENOID (EXCEPT BUILT-UP EXPORT)-2WAY ..334
CAMSHAFT POSITION SENSOR - BLACK 3-WAY...........................334
CLOCKSPRING C1 - YELLOW 2 WAY.....................................334
CLOCKSPRING C2 - NATURAL 5 WAY....................................334
CLOCKSPRING C3 - BLACK 2 WAY.......................................335
CLUTCH INTERLOCK SWITCH (MTX) - BLACK 2 WAY.......................335
CLUTCH INTERLOCK SWITCH JUMPER (EATX) - BLACK 2 WAY..............335
CRANKSHAFT POSITION SENSOR - BLACK 3 WAY.........................335
DATA LINK CONNECTOR - BLACK 16 WAY................................336
EGR SOLENOID - GRAY 2 WAY..........................................336
ENGINE COOLANT TEMPERATURE SENSOR - BLACK 2 WAY................336
ENGINE OIL PRESSURE SWITCH - GREEN 2 WAY.........................336
EVAP/PURGE SOLENOID - BLACK 2 WAY.................................337
DUTY CYCLE EVAP/PURGE SOLENOID...................................337
FUEL INJECTOR NO. 1 (2.0L/2.4L) - BLACK 2 WAY..........................337
FUEL INJECTOR NO. 1 (3.3L/3.8L) - BLACK 2 WAY..........................338
FUEL INJECTOR NO. 2 (2.OL/2.4L) - BLACK 2 WAY.........................338
FUEL INJECTOR NO. 2 (3.3L/3.8L) - BLACK 2 WAY..........................338
FUEL INJECTOR NO. 3 (3.3L/3.8L)- BLACK 2 WAY..........................338
FUEL INJECTOR NO. 3 (2.0L/2.4L) - BLACK 2 WAY..........................339
FUEL INJECTOR NO. 4 (3.3L/3.8L) - BLACK 2 WAY..........................339
FUEL INJECTOR NO. 4 (2.0L/2.4L) - BLACK 2 WAY..........................339
FUEL INJECTOR NO. 5 (3.3L/3.8L) - BLACK 2 WAY..........................339
FUEL INJECTOR NO. 6 (3.3L/3.8L) - BLACK 2 WAY..........................340
FUEL TANK MODULE - LIGHT GRAY 4 WAY...............................340
GENERATOR (GENERATOR SIDE).......................................340
GENERATOR - BLACK 3 WAY...........................................340
IDLE AIR CONTROL MOTOR - BLACK 4 WAY..............................341
IGNITION COIL PACK (2.0L/2.4L) - BLACK 3 WAY...........................341
IGNITION COIL PACK (3.3L/3.8L) - BLACK 4 WAY...........................341
INSTRUMENT CLUSTER - BLACK 13 WAY.................................341
INTAKE AIR TEMPERATURE/MANIFOLD ABSOLUTE PRESSURE SENSOR (2.0L) -
GRAY4 WAY..........................................................342
INTAKE AIR TEMPERATURE SENSOR (2.4L) - GRAY 2 WAY..................342
KNOCK SENSOR - GRAY 2 WAY.........................................342
LEAK DETECTION PUMP - LT. GRAY 4 WAY...............................342
MANIFOLD ABSOLUTE PRESSURE SENSOR (2.4L/3.3L/3.8L) - BLACK 3 WAY. . .343
OUTPUT SPEED SENSOR - GRAY 2 WAY.................................343
OXYGEN SENSOR (SENSOR SIDE)......................................343
OXYGEN SENSOR 1/1 UPSTREAM - GRAY 4 WAY..........................343
OXYGEN SENSOR 1/2 DOWNSTREAM - BLACK 4 WAY.....................344
PARK/NEUTRAL POSITION SWITCH (ATX) - BLACK 3 WAY...................344
FUSES...............................................................346
A/C COMPRESSOR CLUTCH RELAY......................................346
AUTOMATIC SHUT DOWN RELAY (GAS)..................................346
CIGAR LIGHTER/ACCESSORY RELAY....................................346
DIESEL POWER RELAY................................................347
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1.0 INTRODUCTION
The procedures contained in this manual include
specifications, instructions, and graphics needed to
diagnose the PCM Powertrain System. The diag-
nostics in this manual are based on the failure
condition or symptom being present at time of
diagnosis.
Please follow the recommendations below when
choosing your diagnostic path.
1. First make sure the DRBIIItis communicating
with the appropriate modules; ie., if the DRBIIIt
displays a ``No Response'' condition, you must
diagnose this first before proceeding.
2. Read DTC's (diagnostic trouble codes) with the
DRBIIIt.
3. If no DTC's are present, identify the customer
complaint.
4. Once the DTC or customer complaint is identi-
fied, locate the matching test in the Table of
Contents and begin to diagnose the symptom.
All component location views are in Section 8.0.
All connector pinouts are in Section 9.0. All system
schematics are in Section 10.0.
An * placed before the symptom description indi-
cates a customer complaint.
When repairs are required, refer to the appropri-
ate service manual for the proper removal and
repair procedure.
Diagnostic procedures change every year. New
diagnostic systems may be added; carryover sys-
tems may be enhanced. READ THIS MANUAL
BEFORE TRYING TO DIAGNOSE A VEHICLE
CODE. It is recommended that you review the
entire manual to become familiar with all new and
changed diagnostic procedures.
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 the
following 2000 Chrysler Caravan Voyager vehicles
equipped with the 2.0L, 2.4L DOHC, 3.0L MPI,
3.3L/3.8L MPI, or 3.3L E85 compatible Engine.
1.2 SIX-STEP TROUBLESHOOTING
PROCEDURE
Diagnosis of the powertrain control module
(PCM) is done in six basic steps:
²verification of complaint
²verification of any related symptoms
²symptom analysis
²problem isolation
²repair of isolated problem
²verification of proper operation
2.0 IDENTIFICATION OF
SYSTEM
The Powertrain Control Module (PCM) monitors
and controls:
²Fuel system
²Ignition system
²charging system
²speed control system
²cooling system
3.0 SYSTEM DESCRIPTION AND
FUNCTIONAL OPERATION
3.1 GENERAL DESCRIPTION
These Sequential Fuel Injection (SFI) engine sys-
tems have the latest in technical advances. The
on-board Euro Stage III On-Board Diagnostic incor-
porated with the powertrain control module (PCM)
are intended to assist the field technician in repair-
ing vehicle problems by the quickest means.
3.2 FUNCTION OPERATION
3.2.1 FUEL CONTROL
The PCM controls the air/fuel ratio of the engine
by varying fuel injector on time. Mass air flow is
calculated using the speed density method using
engine speed, manifold absolute pressure, and air
temperature change.
Different fuel calculation strategies are used de-
pendent on the operational state of the engine.
During crank mode, a prime shot fuel pulse is
delivered followed by fuel pulses determined by a
crank time strategy. Cold engine operation is deter-
mined via an open loop strategy until the O2
sensors have reached operating temperature. At
this point, the strategy enters a closed loop mode
where fuel requirements are based upon the state of
the O2 sensors, engine speed, MAP, throttle posi-
tion, air temperature, battery voltage, and coolant
temperature.
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GENERAL INFORMATION
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3.2.3 OTHER CONTROLS
CHARGING SYSTEM
The charging system is turned on when the
engine is started and ASD relay energized. When
the ASD relay is on, ASD output voltage is supplied
to the ASD sense circuit at the PCM. This voltage is
connected in some cases, through the PCM and
supplied to one of the generator field terminals
(Gen Source +). All others, the Gen field is con-
nected directly to the ASD output voltage. The
amount of current produced by the generator is
controlled by the Electronic Voltage Regulator
(EVR) circuitry, in the PCM. A battery temperature
sensor, located either in the battery tray, using the
ambient sensor, or in the PCM itself, is used to
sense battery temperature. This temperature along
with sensed line voltage, is used by the PCM to vary
the battery charging rate. This is done by cycling
the ground path to the other generator field termi-
nal (Gen field driver).
SPEED CONTROL SYSTEM
The PCM controls vehicle speed by operation of
the speed control servo vacuum and vent solenoids.
Energizing the vacuum solenoid applies vacuum to
the servo to increase throttle position. Operation of
the vent solenoid slowly releases the vacuum allow-
ing throttle position to decrease. A special dump
solenoid allows immediate release of throttle posi-
tion caused by braking, cruise control switch turned
off, shifting into neutral, excessive RPM (tires spin-
ning) or ignition key off.
3.2.4 PCM OPERATING MODES
As input signals to the powertrain control module
(PCM) change, the PCM adjusts its response to
output devices. For example, the PCM must calcu-
late a different injector pulse width and ignition
timing for idle than it does for wide open throttle.
There are several different modes of operation that
determine how the PCM responds to the various
input signals.
There are two types of engine control operation:
open loopandclosed loop.
In open loop operation, the PCM receives input
signals and responds according to preset program-
ming. Inputs from the heated oxygen sensors are
not monitored.
In closed loop operation, the PCM monitors the
inputs from the heated oxygen sensors. This input
indicates to the PCM whether or not the calculated
injector pulse width results in the ideal air-fuel
ratio of 14.7 parts air to 1 part fuel. By monitoring
the exhaust oxygen content through the oxygen
sensor, the PCM can fine tune injector pulse width.
Fine tuning injector pulse width allows the PCM toachieve the lowest emission levels while maintain-
ing optimum fuel economy.
The engine start-up (crank), engine warm-up,
and wide open throttle modes are open loop modes.
Under most operating conditions, closed loop modes
occur with the engine at operating temperature.
IGNITION SWITCH ON (ENGINE OFF) MODE
When the ignition switch activates the fuel injec-
tion system, the following actions occur:
1. The PCM determines atmospheric air pressure
from the MAP sensor input to determine basic
fuel strategy.
2. The PCM monitors the engine coolant tempera-
ture sensor and throttle position sensor input.
The PCM modifies fuel strategy based on this
input.
When the key is in the ªonº position and the
engine is not running (zero rpm), the auto shut-
down relay and fuel pump relay are not energized.
Therefore, voltage is not supplied to the fuel pump,
ignition coil, and fuel injectors.
Engine Start-up Mode -This is an open loop
mode. The following actions occur when the starter
motor is engaged:
1. The auto shutdown and fuel pump relays are
energized. If the PCM does not receive the cam-
shaft and crankshaft signal within approxi-
mately one second, these relays are de-
energized.
2. The PCM energizes all fuel injectors until it
determines crankshaft position from the cam-
shaft and crankshaft signals. The PCM deter-
mines crankshaft position within one engine
revolution. After the crankshaft position has
been determined, the PCM energizes the fuel
injectors in sequence. The PCM adjusts the in-
jector pulse width and synchronizes the fuel
injectors by controlling the fuel injectors' ground
paths.
3. Once the engine idles within 64 rpm of its target
engine speed, the PCM compares the current
MAP sensor value with the value received dur-
ing the ignition switch on (zero rpm) mode. A
diagnostic trouble code is written to PCM mem-
ory if a minimum difference between the two
values is not found.
Once the auto shutdown and fuel pump relays
have been energized, the PCM determines the fuel
injector pulse width based on the following:
± engine coolant temperature
± manifold absolute pressure
± intake air temperature
± engine revolutions
± throttle position
4
GENERAL INFORMATION
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The PCM determines the spark advance based on
the following:
± engine coolant temperature
± crankshaft position
± camshaft position
± intake air temperature
± manifold absolute pressure
± throttle position
Engine Warm-Up Mode -This is an open loop-
mode. The PCM adjusts injector pulse width and
controls injector synchronization by controlling the
fuel injectors' ground paths. The PCM adjusts igni-
tion timing and engine idle speed. The PCM adjusts
the idle speed by controlling the idle air control
motor and spark advance.
Cruise or Idle Mode -When the engine is at
normal operating temperature, this is a closed loop
mode.
Acceleration Mode -This is a closed loop mode.
The PCM recognizes an increase in throttle position
and a decrease in manifold vacuum as engine load
increases. In response, the PCM increases the in-
jector pulse width to meet the increased load. The
A/C compressor may be de-energized for a short
period of time.
Deceleration -This is a closed loop mode. The
PCM recognizes a decrease in throttle position and
an increase in manifold vacuum as engine load
decreases. In response, the PCM decreases the
injector pulse width to meet the decreased load.
Full injector shut off may be obtained during high
speed deceleration.
Wide Open Throttle Mode -This is an open
loop mode. The throttle position sensor notifies the
PCM of a wide open throttle condition. Once a wide
open throttle is sensed, the PCM de-energizes the
A/C compressor clutch relay for 15 seconds.
3.2.5 NON-MONITORED CIRCUITS
The PCM does not monitor the following circuits,
systems, and conditions even though they could
have malfunctions that result in driveability prob-
lems. A diagnostic code may not be displayed for the
following conditions. However, problems with these
systems may cause a diagnostic code to be displayed
for other systems. For example, a fuel pressure
problem will not register a diagnostic code directly,
but could cause a rich or lean condition. This could
cause an oxygen sensor, fuel system, or misfire
monitor trouble code to be stored in the PCM.
Engine Timing -The PCM cannot detect an
incorrectly indexed timing chain, camshaft
sprocket, or crankshaft sprocket. The PCM also
cannot detect an incorrectly indexed distributor.(*)
Fuel Pressure -Fuel pressure is controlled by
the fuel pressure regulator. The PCM cannot detecta clogged fuel pump inlet filter, clogged in-line filter,
or a pinched fuel supply.(*)
Fuel Injectors -The PCM cannot detect if a fuel
injector is clogged, the pintle is sticking, or the
wrong injectors are installed.(*)
Fuel Requirements -Poor quality gasoline can
cause problems such as hard starting, stalling, and
stumble. Use of methanol-gasoline blends may re-
sult in starting and driveability problems. See indi-
vidual symptoms and their definitions in Section
6.0 (Glossary of Terms)
PCM Grounds -The PCM cannot detect a poor
system ground. However, a diagnostic trouble code
may be stored in the PCM as a result of this
condition.
Throttle Body Air Flow -The PCM cannot
detect a clogged or restricted air cleaner inlet or
filter element.(*)
Exhaust System -The PCM cannot detect a
plugged, restricted, or leaking exhaust system.(*)
Cylinder Compression -The PCM cannot de-
tect uneven, low, or high engine cylinder compres-
sion.(*)
Excessive Oil Consumption -Although the
PCM monitors the exhaust stream oxygen content
through the oxygen sensor when the system is in a
closed loop, it cannot determine excessive oil con-
sumption.
(*)NOTE: ANY OF THESE CONDITIONS
COULD RESULT IN A RICH OR LEAN
CONDITION CAUSING AN OXYGEN SENSOR
TROUBLE CODE TO BE STORED IN THE
PCM, OR THE VEHICLE MAY EXHIBIT ONE
OR MORE OF THE DRIVEABILITY
SYMPTOMS LISTED IN THE TABLE OF
CONTENTS.
3.2.6 SKIS OVERVIEW
The Sentry Key Immobilizer System (SKIS) is an
immobilizer system design to prevent unauthorized
vehicle operation. The system consists of a Sentry
Key Immobilizer Module (SKIM), ignition key(s)
equipped with a transponder chip and engine con-
troller. When the ignition switch is turned on, the
SKIM interrogates the ignition key. If the ignition
key is ``Valid'', the SKIM sends a CCD Bus message
to the engine controller indicating the presence of a
valid igntion key. Upon receiving a ``Valid'' key
signal the PCM will allow the engine to continue to
operate.
3.2.7 SKIM ON-BOARD DIAGNOSTICS
The SKIM has been programmed to transmit and
monitor many different coded messages as well as
CCD Bus messages. This monitoring is called ``On
Board Diagnosis''.
5
GENERAL INFORMATION
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