2002 JEEP LIBERTY Fuel system

ity of the headlamp and dash wire harness connector
for the washer fluid level switch and a good ground.
There should be continuity. If OK, go to Step 2. If not
OK, repair the open ground circuit to ground (G111)
as required.
(2) Remove the instrument cluster from the instru-
ment panel. Check for continuity between the washer
fluid sense circuit cavities of the headlamp and dash
wire harness connector for the washer fluid level
switch and the instrument panel wire harness con-
nector (Connector C2) for the instrument cluster. If
OK, replace the faulty washer fluid level switch. If
not OK, repair the open washer fluid switch sense
circuit between the washer fluid level switch and the
instrument cluster as required.
INDICATOR STAYS ILLUMINATED WITH WASHER
RESERVOIR FULL
(1) Disconnect and isolate the battery negative
cable. Disconnect the headlamp and dash wire har-
ness connector for the washer fluid level switch from
the washer fluid level switch connector receptacle.
Check for continuity between the ground circuit ter-
minal and the washer fluid sense terminal in the
washer fluid level switch connector receptacle. There
should be no continuity. If OK, go to Step 2. If not
OK, replace the faulty washer fluid level switch.
(2) Remove the instrument cluster from the instru-
ment panel. Check for continuity between the washer
fluid sense circuit cavity of the headlamp and dash
wire harness connector for the washer fluid level
switch and a good ground. There should be no conti-
nuity. If not OK, repair the shorted washer fluid
switch sense circuit between the washer fluid level
switch and the instrument cluster as required.
WATER-IN-FUEL INDICATOR
DESCRIPTION
A water-in-fuel indicator is only found in the
instrument clusters of vehicles equipped with an
optional diesel engine. The water-in-fuel indicator is
located above the coolant temperature gauge and to
the right of the speedometer in the instrument clus-
ter. The water-in-fuel indicator consists of a stencil-
like cutout of the International Control and Display
Symbol icon for ªWater In Fuelº in the opaque layer
of the instrument cluster overlay. The dark outer
layer of the overlay prevents the indicator from being
clearly visible when it is not illuminated. A red Light
Emitting Diode (LED) behind the cutout in the
opaque layer of the overlay causes the icon to appear
in red through the translucent outer layer of the
overlay when the indicator is illuminated from
behind by the LED, which is soldered onto the
instrument cluster electronic circuit board. Thewater-in-fuel indicator is serviced as a unit with the
instrument cluster.
OPERATION
The water-in-fuel indicator gives an indication to
the vehicle operator when there is excessive water in
the fuel system. This indicator is controlled by a
transistor on the instrument cluster electronic circuit
board based upon cluster programming and elec-
tronic messages received by the cluster from the
Powertrain Control Module (PCM) over the Program-
mable Communications Interface (PCI) data bus. The
water-in-fuel indicator Light Emitting Diode (LED) is
completely controlled by the instrument cluster logic
circuit, and that logic will only allow this indicator to
operate when the instrument cluster receives a bat-
tery current input on the fused ignition switch out-
put (run-start) circuit. Therefore, the LED will
always be off when the ignition switch is in any posi-
tion except On or Start. The LED only illuminates
when it is provided a path to ground by the instru-
ment cluster transistor. The instrument cluster will
turn on the water-in-fuel indicator for the following
reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the water-in-fuel indicator
is illuminated for about three seconds as a bulb test.
²Water-In-Fuel Lamp-On Message- Each time
the cluster receives a water-in-fuel lamp-on message
from the PCM indicating there is excessive water in
the diesel fuel system, the water-in-fuel indicator will
be illuminated. The indicator remains illuminated
until the cluster receives a water-in-fuel lamp-off
message, or until the ignition switch is turned to the
Off position, whichever occurs first.
²Actuator Test- Each time the cluster is put
through the actuator test, the water-in-fuel indicator
will be turned on, then off again during the bulb
check portion of the test to confirm the functionality
of the LED and the cluster control circuitry.
The PCM continually monitors the water-in-fuel
sensor to determine whether there is excessive water
in the diesel fuel. The PCM then sends the proper
water-in-fuel lamp-on and lamp-off messages to the
instrument cluster. For further diagnosis of the
water-in-fuel indicator or the instrument cluster cir-
cuitry that controls the indicator, (Refer to 8 - ELEC-
TRICAL/INSTRUMENT CLUSTER - DIAGNOSIS
AND TESTING). For proper diagnosis of the water-
in-fuel-sensor, the PCM, the PCI data bus, or the
electronic message inputs to the instrument cluster
that control the water-in-fuel indicator, a DRBIIIt
scan tool is required. Refer to the appropriate diag-
nostic information.
KJINSTRUMENT CLUSTER 8J - 37
WASHER FLUID INDICATOR (Continued)

The CMTC may also be integrated with the Uni-
versal Transmitter. If so, your CMTC module will
have three buttons centered together between the
outer four buttons. Below the three buttons are cor-
responding dots to indicate which button you are
using.
The Compass Mini-Trip Computer includes the fol-
lowing display options:
²Compass and thermometer- provides the out-
side temperature and one of eight compass readings
to indicate the direction the vehicle is facing.
²Average fuel economy- shows the average
fuel economy since the last trip computer reset.
²Distance to empty- shows the estimated dis-
tance that can be travelled with the fuel remaining
in the fuel tank. This estimated distance is computed
using the average miles-per-gallon from the last 30
gallons of fuel used.
²Instant fuel economy- shows the present fuel
economy based upon the current vehicle distance and
fuel used information.
²Trip odometer- shows the distance travelled
since the last trip computer reset.
²Elapsed time- shows the accumulated igni-
tion-on time since the last trip computer reset.
²Blank screen- the CMTC compass/thermome-
ter/trip computer VFD is turned off.
If the vehicle is equipped with the optional Univer-
sal Transmitter transceiver, the CMTC will also dis-
play messages and an icon indicating when the
Universal Transmitter is being trained, which of the
three transmitter buttons is transmitting, and when
the transceiver is cleared.
Data input for all CMTC functions, including VFD
dimming level, is received through PCI data bus
messages. The CMTC module uses its internal pro-
gramming and all of its data inputs to calculate and
display the requested data. If the data displayed is
incorrect, perform the self-diagnostic tests as
described in this group. If these tests prove inconclu-
sive, the use of a DRBIIItscan tool and the proper
Diagnostic Procedures manual are recommended for
further testing of the CMTC module and the PCI
data bus.
The CMTC module cannot be repaired, and is
available for service only as a unit. This unit
includes the push button switches and the plastic
module and display lens. If any of these components
is faulty or damaged, the complete CMTC module
must be replaced. The incandescent bulbs used for
CMTC push button back-lighting are available for
service replacement.
DESCRIPTION - COMPASS
While in the compass/thermometer mode, the com-
pass will display the direction in which the vehicle ispointed using the eight major compass headings
(Examples: north is N, northeast is NE). The self-cal-
ibrating compass unit requires no adjusting in nor-
mal use. The only calibration that may prove
necessary is to drive the vehicle in three complete
circles at 5 to 8 kilometers-per-hour (3 to 5 miles-per-
hour), on level ground, in not less than forty-eight
seconds. This will reorient the compass unit to its
vehicle.
The compass unit also will compensate for magne-
tism the body of the vehicle may acquire during nor-
mal use. However, avoid placing anything magnetic
directly on the roof of the vehicle. Magnetic mounts
for an antenna, a repair order hat, or a funeral pro-
cession flag can exceed the compensating ability of
the compass unit if placed on the roof panel. Mag-
netic bit drivers used on the fasteners that hold the
overhead console assembly to the roof header can
also affect compass operation. If the vehicle roof
should become magnetized, the demagnetizing and
calibration procedures found in this group may be
required to restore proper compass operation.
DESCRIPTION - THERMOMETER
The thermometer displays the outside ambient
temperature in whole degrees. The temperature dis-
play can be toggled from Fahrenheit to Celsius by
using the U.S./Metric button. The displayed temper-
ature is not an instant reading of conditions, but an
average temperature. It may take the thermometer
display several minutes to respond to a major tem-
perature change, such as driving out of a heated
garage into winter temperatures.
When the ignition switch is turned to the Off posi-
tion, the last displayed temperature reading stays in
the Body Control Module (BCM) unit memory. When
the ignition switch is turned to the On position
again, the CMTC will display the memory tempera-
ture for one minute; then update the display to the
current average temperature reading within five
minutes.
The thermometer function is supported by an
ambient temperature sensor. The sensor is mounted
outside the passenger compartment near the front
and center of the vehicle, and is hard wired to the
Body Control Module (BCM). The BCM sends tem-
perature status messages to the CMTC module over
the PCI data bus network. The ambient temperature
sensor is available as a separate service item, refer to
additional information later in this section.
OPERATION
The compass mini-trip computer operates when the
ignition is in the ON position. The VFD will display
the last display before ignition was turned OFF. The
four outer buttons operate:
KJMESSAGE SYSTEMS 8M - 5
COMPASS/MINI-TRIP COMPUTER (Continued)

²STEP
²C/T - Compass/Temperature
²US/M - English/Metric
²RESET
1. STEP BUTTON
Pressing the STEP button selects one of the follow-
ing 6 displays:
²Average fuel economy
²Distance to empty
²Instantaneous fuel economy
²Trip odometer
²Elapsed time
²Blank Screen
2. C/T (COMPASS/TEMPERATURE)
BUTTON
Pressing the C/T button selects the Compass/Tem-
perature display.
3. US/M (ENGLISH/METRIC
MEASUREMENT) BUTTON
Pressing the US/M button switches the display
units between English and Metric readings.
4. RESET BUTTON
Pressing the RESET button resets the function on
the display, provided that function can be reset. The
functions which can be reset are Average fuel econ-
omy, Trip odometer and Elapsed time.
Global ResetThis feature allows all three dis-
plays (Average fuel economy, Trip odometer and
Elapsed time) to be reset easily, by pressing the
RESET button twice within three seconds with any
of the screens in display. This eliminates the need to
reset each display individually.
The RESET button is also used to set the variance
and/or calibrate the compass. Refer to the Variance
Procedure and Calibration Procedure in this section.
For more information on the features, control func-
tions and setting procedures for the CMTC module,
see the owner's manual in the vehicle glove box.
DIAGNOSIS AND TESTING - COMPASS
MINI-TRIP COMPUTER
The following diagnostic procedure can be used if
the compass mini-trip computer is not operational in
any way. If the problem is specific to a individual
CMTC display, go to the appropriate display title
noted below and diagnose using the information pro-
vided on how these displays are generated.
(1) Remove the overhead console from the head-
liner (Refer to 8 - ELECTRICAL/OVERHEAD CON-
SOLE - REMOVAL).
(2) Using a ohmmeter, check the ground circuit
cavity of the compass mini-trip computer electricalconnector for proper continuity to ground. Continuity
should be present, If OK go to Step 3, If not OK
repair the open or shorted ground circuit as required.
NOTE: Connect the negative battery cable before
proceeding.
(3) Using a voltmeter, check the fused (B+) circuit
cavity of the compass mini-trip computer electrical
connector for 12v. Voltage should be present, If OK go
to Step 4, If not OK repair the open or shorted fused
(B+) circuit as required.
(4) Using a voltmeter, check the fused ignition
switch output circuit cavity of the compass mini-trip
computer electrical connector for 12v with Key ON.
Voltage should be present, If OK, replace the inoper-
ative CMTC module, If not OK repair the open or
shorted fused ignition switch output circuit as
required.
TEMPERATURE
The compass mini-trip computer receives Program-
mable Communications Interface bus (PCI bus) mes-
sages from the Body Control Module (BCM) for all
displayed information except the compass display. If
a dash (-) is displayed, the compass mini-trip com-
puter is not receiving a PCI bus message from the
BCM. To check out the PCI bus line and the BCM,
use the DRB llltscan tool and proper Body Diagnos-
tic Procedure Manual.
If the compass mini-trip computer displays a tem-
perature more than 54É C (130É F), check for a short
circuit between the temperature sensor and the
BCM.
If the compass mini-trip computer displays a tem-
perature less than -40É C (-67É F), check for an open
circuit between the temperature sensor and the
BCM.
AVERAGE FUEL ECONOMY
The compass mini-trip computer receives average
fuel economy information from the BCM over the PCI
bus line. If the compass mini-trip computer displays
-.- instead of an average fuel economy value, it is not
receiving a PCI bus message for the average fuel
economy from the BCM. To check out the PCI bus
line and the BCM use the DRB llltscan tool and
proper Body Diagnostic Procedure Manual.
DISTANCE TO EMPTY
The compass mini-trip computer receives distance
to empty information from the BCM over the PCI bus
line. If compass mini-trip computer displays a dash
(-) instead of a distance to empty value, it is not
receiving a PCI bus message for the distance to
empty from the BCM. To check out the PCI bus line
8M - 6 MESSAGE SYSTEMSKJ
COMPASS/MINI-TRIP COMPUTER (Continued)

and the BCM use the DRB llltscan tool and proper
Body Diagnostic Procedure Manual.
INSTANTANEOUS FUEL ECONOMY
The compass mini-trip computer receives instanta-
neous fuel economy information from the BCM over
the PCI bus line. If compass mini-trip computer dis-
plays a dash (-) instead of an instantaneous fuel
economy value, it is not receiving a PCI bus message
for the instantaneous fuel economy from the BCM. To
check out the PCI bus line and the BCM use the
DRB llltscan tool and proper Body Diagnostic Pro-
cedure Manual.
TRIP ODOMETER
The compass mini-trip computer receives trip
odometer information from the Cluster over the PCI
bus line. If compass mini-trip computer displays
dashes - - instead of the trip odometer value, it is not
receiving a PCI bus message for the trip odometer
from the cluster. To check out the PCI bus line and
the Cluster, use the DRB llltscan tool and proper
Body Diagnostic Procedure Manual.
ELAPSED TIME
The compass mini-trip computer receives a PCI
bus message containing elapsed time information. If
compass mini-trip computer displays dashes --
instead of the elapsed time, it is not receiving a PCI
bus message for the elapsed time from the BCM. To
check out the PCI bus line and the BCM, use the
DRB llltscan tool and proper Body Diagnostic Pro-
cedure Manual.
COMPASS DISPLAY
To display the vehicle direction, the compass mini-
trip computer processes information from a sensor
internal to the module. The compass mini-trip com-
puter is self- calibrating and requires only variance
adjustments dependent upon location. The compass
mini-trip computer displays the label CAL whenever
the compass is in the fast calibration mode.
If all three of the following conditions listed below
occur, the vehicle must be demagnetized.
²Compass portion of the display is blank
²Temperature portion of the display is OK
²The label CAL is illuminated
If demagnetizing the vehicle is needed, refer to the
demagnetizing procedure in this section. After
demagnetizing, to calibrate the compass refer to Cal-
ibration Procedure and to set the variance refer to
Variance Procedure, both within this section. If the
compass portion of the display is still blank, replace
the compass mini-trip computer.
COMPASS MINI-TRIP COMPUTER - SELF
DIAGNOSTIC TEST
(1) With the ignition switch in the OFF position
simultaneously press the C/T and STEP buttons and
hold.
(2) Turn the ignition switch ON, then release C/T
and STEP buttons.
(3) The Compass mini-trip computer should light
all segments on the VF Display Screen for 2-4 sec-
onds. Check for segments that are not illuminated.
(4) If the compass mini-trip computer displays
PASS, the module is OK.
(5) If the compass mini-trip computer displays
FAIL, replace the module.
(6) If the compass mini-trip computer displays
bUS, check for an open or a short on the PCI bus
communication circuit.
(7) Press the C/T or the STEP button to exit the
self-diagnostic test.
REMOVAL
(1) Remove overhead console, refer to Console
Removal and Installation in this section.
(2) Remove mounting screws and release the map
lamp wire connector from the compass mini-trip com-
puter. (Fig. 6).
Fig. 6 Compass Mini-Trip Computer Retaining
Screws
1 - LAMPS
2 - MOUNTING SCREWS
KJMESSAGE SYSTEMS 8M - 7
COMPASS/MINI-TRIP COMPUTER (Continued)

WIRING
TABLE OF CONTENTS
page page
WIRING DIAGRAM INFORMATION...... 8Wa-01-1
COMPONENT INDEX................. 8Wa-02-1
POWER DISTRIBUTION.............. 8Wa-10-1
JUNCTION BLOCK................... 8Wa-12-1
GROUND DISTRIBUTION............. 8Wa-15-1
BUS COMMUNICATIONS............. 8Wa-18-1
CHARGING SYSTEM................. 8Wa-20-1
STARTING SYSTEM................. 8Wa-21-1
FUEL/IGNITION SYSTEM............. 8Wa-30-1
TRANSMISSION CONTROL SYSTEM.... 8Wa-31-1
VEHICLE SPEED CONTROL........... 8Wa-33-1
ANTILOCK BRAKES.................. 8Wa-35-1
VEHICLE THEFT SECURITY SYSTEM.... 8Wa-39-1
INSTRUMENT CLUSTER.............. 8Wa-40-1
HORN/CIGAR LIGHTER/POWER OUTLET . 8Wa-41-1
AIR CONDITIONING-HEATER.......... 8Wa-42-1
AIRBAG SYSTEM................... 8Wa-43-1
INTERIOR LIGHTING................. 8Wa-44-1BODY CONTROL MODULE............ 8Wa-45-1
AUDIO SYSTEM.................... 8Wa-47-1
REAR WINDOW DEFOGGER........... 8Wa-48-1
OVERHEAD CONSOLE................ 8Wa-49-1
FRONT LIGHTING................... 8Wa-50-1
REAR LIGHTING.................... 8Wa-51-1
TURN SIGNALS..................... 8Wa-52-1
WIPERS........................... 8Wa-53-1
TRAILER TOW...................... 8Wa-54-1
POWER WINDOWS.................. 8Wa-60-1
POWER DOOR LOCKS............... 8Wa-61-1
POWER MIRRORS.................. 8Wa-62-1
POWER SEAT...................... 8Wa-63-1
POWER SUNROOF.................. 8Wa-64-1
SPLICE INFORMATION............... 8Wa-70-1
CONNECTOR PIN-OUTS.............. 8Wa-80-1
CONNECTOR/GROUND/
SPLICE LOCATION................. 8Wa-91-1 KJWIRING
8Wa-1

8W-30 FUEL/IGNITION SYSTEM
Component Page
A/C Compressor Clutch.............. 8Wa-30-34
A/C Compressor Clutch Relay..... 8Wa-30-34, 2, 3
A/C High Pressure Switch............ 8Wa-30-29
A/C Low Pressure Switch.......... 8Wa-30-8, 29
A/C Pressure Transducer....... 8Wa-30-11, 23, 12
Accelerator Pedal Position Sensor...... 8Wa-30-27
Auto Shut Down Relay . . 8Wa-30-13, 14, 15, 24, 28,
31, 16, 17, 2
Battery Temperature Sensor........ 8Wa-30-30, 7
Blower Motor Relay................. 8Wa-30-31
Body Control Module.............. 8Wa-30-8, 33
Boost Pressure Sensor............ 8Wa-30-26, 28
Brake Lamp Switch............ 8Wa-30-8, 32, 33
Cabin Heater...................... 8Wa-30-34
Cabin Heater Relay................. 8Wa-30-34
Camshaft Position Sensor....... 8Wa-30-10, 9, 28
Capacitor...................... 8Wa-30-19, 17
Clockspring..................... 8Wa-30-33, 7
Clutch Switch Override Relay.... 8Wa-30-13, 8, 32
Coil On Plug No. 1................. 8Wa-30-19
Coil On Plug No. 2................. 8Wa-30-20
Coil On Plug No. 3................. 8Wa-30-19
Coil On Plug No. 4................. 8Wa-30-20
Coil On Plug No. 5................. 8Wa-30-19
Coil On Plug No. 6................. 8Wa-30-20
Coil Rail......................... 8Wa-30-17
Controller Antilock Brake............ 8Wa-30-33
Crankshaft Position Sensor...... 8Wa-30-10, 9, 27
Data Link Connector.............. 8Wa-30-25, 6
Diagnostic Junction Port........... 8Wa-30-25, 6
EGR Solenoid..................... 8Wa-30-30
Engine Control Module . . 8Wa-30-24, 25, 26, 27, 28,
29, 30, 31, 32, 33, 34, 35, 36
Engine Coolant Temperature Sensor . 8Wa-30-11, 28,
12
Engine Oil Pressure Sensor..... 8Wa-30-11, 28, 12
Evap/Purge Solenoid................. 8Wa-30-2
Fuel Heater....................... 8Wa-30-31
Fuel Heater Relay.................. 8Wa-30-31
Fuel Injector No. 1............... 8Wa-30-18, 36
Fuel Injector No. 2............... 8Wa-30-18, 36
Fuel Injector No. 3............... 8Wa-30-18, 36
Fuel Injector No. 4............... 8Wa-30-18, 36
Fuel Injector No. 5................. 8Wa-30-18
Fuel Injector No. 6................. 8Wa-30-18
Fuel Pressure Sensor............... 8Wa-30-36
Fuel Pressure Solenoid.............. 8Wa-30-31
Fuel Pump Module............. 8Wa-30-30, 4, 5
Fuel Pump Relay.............. 8Wa-30-4, 2, 3, 5
Fuse 2........................... 8Wa-30-23
Fuse 6................... 8Wa-30-24, 28, 31, 2Component Page
Fuse 10.......................... 8Wa-30-35
Fuse 11.......................... 8Wa-30-35
Fuse 12....................... 8Wa-30-31, 33
Fuse 15...................... 8Wa-30-25, 2, 3
Fuse 16...... 8Wa-30-13, 14, 15, 24, 30, 34, 35, 16
Fuse 21.......................... 8Wa-30-34
Fuse 24...................... 8Wa-30-31, 2, 3
Fuse 26.................. 8Wa-30-18, 24, 17, 2
Fuse 28.......................... 8Wa-30-13
G100.................... 8Wa-30-19, 27, 17, 3
G101............................ 8Wa-30-23
G103................. 8Wa-30-15, 23, 31, 34, 16
G104............................ 8Wa-30-27
G111 ............................ 8Wa-30-31
G112 .......................... 8Wa-30-8, 23
G320........................... 8Wa-30-4, 5
Generator.................. 8Wa-30-24, 4, 3, 5
Glow Plug Assembly................ 8Wa-30-35
Glow Plug Relay No. 1.............. 8Wa-30-35
Glow Plug Relay No. 2.............. 8Wa-30-35
Idle Air Control Motor............ 8Wa-30-21, 22
Ignition Switch.................... 8Wa-30-32
Intake Air Temperature Sensor..... 8Wa-30-11, 12
Junction Block........... 8Wa-30-25, 31, 33, 2, 3
Knock Sensor...................... 8Wa-30-8
Leak Detection Pump.............. 8Wa-30-4, 5
Left Speed Control Switch.......... 8Wa-30-33, 7
Manifold Absolute Pressure Sensor . . 8Wa-30-11, 12
Oxygen Sensor 1/1 Upstream...... 8Wa-30-14, 15
Oxygen Sensor 1/2 Downstream . 8Wa-30-13, 14, 15
Oxygen Sensor 2/1 Upstream......... 8Wa-30-16
Oxygen Sensor 2/2 Downstream.... 8Wa-30-13, 16
Oxygen Sensor Downstream Relay . . 8Wa-30-13, 15,
16
Power Distribution Center . . 8Wa-30-13, 14, 15, 23,
24, 28, 30, 31, 34, 35, 16, 17, 2, 3
Power Steering Pressure Switch....... 8Wa-30-23
Powertrain Control Module . . . 8Wa-30-10, 13, 20, 8,
11, 14, 15, 18, 19, 21, 9, 23, 4, 12, 16, 17, 2, 22, 3,
6, 7, 5
Radiator Fan Motor................. 8Wa-30-23
Radiator Fan Relay................. 8Wa-30-23
Right Speed Control Switch......... 8Wa-30-33, 7
Shifter Assembly................. 8Wa-30-8, 32
Speed Control Servo................. 8Wa-30-8
Starter Motor Relay................ 8Wa-30-13
Throttle Position Sensor.......... 8Wa-30-21, 22
Transfer Case Position Sensor.... 8Wa-30-9, 23, 32
Transmission Control Module . . 8Wa-30-10, 8, 22, 6
Transmission Solenoid/Trs Assembly.... 8Wa-30-10
Water In Fuel Sensor............... 8Wa-30-29
KJ8W-30 FUEL/IGNITION SYSTEM8Wa-30-1

8W-31 TRANSMISSION CONTROL SYSTEM
Component Page
A/C Compressor Clutch Relay.......... 8Wa-31-3
Auto Shut Down Relay............... 8Wa-31-3
Back-Up Lamp Switch............... 8Wa-31-4
Brake Lamp Switch................. 8Wa-31-5
Crankshaft Position Sensor............ 8Wa-31-6
Data Link Connector................. 8Wa-31-6
Diagnostic Junction Port.............. 8Wa-31-3
Engine Control Module............... 8Wa-31-6
Fuel Pump Relay................... 8Wa-31-3
Fuse 5............................ 8Wa-31-2
Fuse 15........................... 8Wa-31-3
Fuse 28........................... 8Wa-31-3
Fuse 38........................... 8Wa-31-5
Fuse 39........................... 8Wa-31-4
G102........................... 8Wa-31-7, 9
G111 ............................. 8Wa-31-2
G301............................. 8Wa-31-5
Input Speed Sensor.................. 8Wa-31-9Component Page
Instrument Cluster.................. 8Wa-31-5
Junction Block.................. 8Wa-31-3, 4, 5
Left Tail/Stop Lamp................. 8Wa-31-4
Line Pressure Sensor................ 8Wa-31-9
Output Speed Sensor................ 8Wa-31-9
Power Distribution Center.......... 8Wa-31-2, 3
Powertrain Control Module........ 8Wa-31-3, 5, 6
Right Tail/Stop Lamp................ 8Wa-31-4
Shifter Assembly.................... 8Wa-31-5
Starter Motor Relay................. 8Wa-31-8
Throttle Position Sensor.............. 8Wa-31-5
Trailer Tow Connector................ 8Wa-31-4
Transfer Case Position Sensor.......... 8Wa-31-5
Transmission Control Module . . 8Wa-31-2, 3, 5, 6, 7,
8, 9
Transmission Control Relay....... 8Wa-31-2, 7, 8
Transmission Solenoid/Trs Assembly . . 8Wa-31-2, 4,
7, 8, 9
KJ8W-31 TRANSMISSION CONTROL SYSTEM8Wa-31-1

DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ENGINE
DIAGNOSIS - INTRODUCTION
Engine diagnosis is helpful in determining the
causes of malfunctions not detected and remedied by
routine maintenance.
These malfunctions may be classified as either per-
formance (e.g., engine idles rough and stalls) or
mechanical (e.g., a strange noise).
(Refer to 9 - ENGINE - DIAGNOSIS AND TEST-
ING)ÐPERFORMANCE and (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)ÐMECHANICAL for
possible causes and corrections of malfunctions.
(Refer to 14 - FUEL SYSTEM/FUEL DELIVERY -
DIAGNOSIS AND TESTING) and (Refer to 14 -
FUEL SYSTEM/FUEL INJECTION - DIAGNOSIS
AND TESTING) for the fuel system diagnosis.Additional tests and diagnostic procedures may be
necessary for specific engine malfunctions that can
not be isolated with the Service Diagnosis charts.
Information concerning additional tests and diagno-
sis is provided within the following diagnosis:
²Cylinder Compression Pressure Test (Refer to 9 -
ENGINE - DIAGNOSIS AND TESTING).
²Cylinder Combustion Pressure Leakage Test
(Refer to 9 - ENGINE - DIAGNOSIS AND TEST-
ING).
²Engine Cylinder Head Gasket Failure Diagnosis
(Refer to 9 - ENGINE/CYLINDER HEAD - DIAGNO-
SIS AND TESTING).
²Intake Manifold Leakage Diagnosis (Refer to 9 -
ENGINE/MANIFOLDS/INTAKE MANIFOLD -
DIAGNOSIS AND TESTING).
DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - PERFORMANCE
CONDITION POSSIBLE CAUSE CORRECTION
ENGINE WILL NOT START 1. Weak battery 1. Charge or replace as necessary.
2. Corroded or loose battery
connections.2. Clean and tighten battery
connections. Apply a coat of light
mineral grease to the terminals.
3. Faulty starter. 3. (Refer to 8 - ELECTRICAL/
STARTING - DIAGNOSIS AND
TESTING).
4. Faulty coil or control unit. 4. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION
COIL - REMOVAL).
5. Incorrect spark plug gap. 5. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG
- CLEANING).
6. Incorrect right bank cam timing. 6. Refer to engine timing in this
section.
7. Dirt or water in fuel system. 7. Clean system and replace fuel
filter.
8.Faulty fuel pump, relay or wiring. 8.Repair or replace as necessary.
9. Faulty cam or crank sensor 9. Refer to Ignition system.
ENGINE STALLS OR ROUGH IDLE 1. Vacuum leak. 1. Inspect intake manifold and
vacuum hoses, repair or replace as
necessary.
2. Faulty crank position sensor 2. Replace crank position sensor.
4. Faulty coil. 4. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION
COIL - REMOVAL).
9 - 4 ENGINE - 3.7LKJ
ENGINE - 3.7L (Continued)