2002 JEEP GRAND CHEROKEE can bus

CONTROLLER ANTILOCK BRAKE - BLACK 24 WAY
CAV CIRCUIT FUNCTION
1 Z101 12BK/OR GROUND
2 B1 18YL/DB RIGHT REAR WHEEL SPEED SENSOR SIGNAL
3 B2 18YL RIGHT REAR WHEEL SPEED SENSOR 12 VOLT
SUPPLY
4- -
5 D25 18VT/YL PCI BUS
6 B6 18WT/DB RIGHT FRONT WHEEL SPEED SENSOR SIGNAL
7 B7 18WT RIGHT FRONT WHEEL SPEED SENSOR 12 VOLT
SUPPLY
8- -
9 A20 12RD/DB FUSED B(+)
10 F20 18DB/PK FUSED IGNITION SWITCH OUTPUT (RUN)
11 D52 18LG/WT (DIESEL) CAN C BUS(+)
12 - -
13 B22 18DG/YL VEHICLE SPEED SENSOR SIGNAL
14 D51 18DG/WT (DIESEL) CAN C BUS(-)
15 - -
16 Z102 12BK/OR GROUND
17 G9 18GY/BK BRAKE FLUID LEVEL SWITCH SENSE
18 L50 18WT/TN PRIMARY BRAKE SWITCH SIGNAL
19 B3 18LG/DB LEFT REAR WHEEL SPEED SENSOR SIGNAL
20 B4 18LG LEFT REAR WHEEL SPEED SENSOR 12 VOLT SUPPLY
21 Z231 18BK GROUND
22 B8 18RD/DB LEFT FRONT WHEEL SPEED SENSOR SIGNAL
23 B9 18RD LEFT FRONT WHEEL SPEED SENSOR 12 VOLT
SUPPLY
24 A10 12RD/DG FUSED B(+)
COOLANT LEVEL SENSOR - LT. GRAY 2 WAY
CAV CIRCUIT FUNCTION
1 G18 20PK/BK (EXCEPT LHD GAS) COOLANT LEVEL SWITCH SENSE
1 G18 18PK/BK (LHD GAS) COOLANT LEVEL SWITCH SENSE
2 Z307 20BK GROUND
CRANKCASE HEATER (DIESEL) - BLACK 2 WAY
CAV CIRCUIT FUNCTION
1 Z18 20BR GROUND
2 F15 20RD/DG FUSED AUTO SHUT DOWN RELAY OUTPUT
8W - 80 - 64 8W-80 CONNECTOR PIN-OUTWJ

ENGINE CONTROL MODULE C1 (DIESEL) - BLACK 81 WAY
CAV CIRCUIT FUNCTION
1 Z108 14BK/DG GROUND
2 Z108 14BK/DG GROUND
3 K20 14DB GENERATOR FIELD CONTROL
4 F142 14RD/DG FUSED AUTO SHUT DOWN RELAY OUTPUT
5 F142 14RD/DG FUSED AUTO SHUT DOWN RELAY OUTPUT
6 D52 18DG/WT CAN C BUS(+)
7 D25 20VT/YL PCI BUS
8 K944 20BR/DG CAMSHAFT POSITION SENSOR GROUND
9 K44 20YL/GY CAMSHAFT POSITION SENSOR SIGNAL
10 - -
11 Y53 20BK/YL BOOST PRESSURE SENSOR SIGNAL
12 K155 20YL/WT MASS AIR FLOW SENSOR SIGNAL
13 Y40 20DG/VT FUEL PRESSURE SENSOR SIGNAL
14 K22 20RD/DB ACCELERATOR PEDAL POSITION SENSOR 2 SIGNAL
15 K81 20DB/DG ACCELERATOR PEDAL POSITION SENSOR 1 SIGNAL
16 Y100 20BR/GY FUEL PRESSURE SENSOR GROUND
17 - -
18 - -
19 F300 20RD/BK BATTERY SENSE (+)
20 Z11 20BK/WT BATTERY SENSE (-)
21 K4 18BK/LB SENSOR GROUND
22 F991 20RD/DB FUSED IGNITION SWITCH OUTPUT (RUN-START)
23 K6 18VT/WT SENSOR REFERENCE VOLTAGE B
24 K3 20BK CRANKSHAFT POSITION SENSOR SIGNAL 1
25 D51 18WT CAN C BUS(-)
26 - -
27 - -
28 - -
29 K77 20BR/WT TRANSFER CASE POSITION SENSOR INPUT
30 G60 20BR/DB ENGINE OIL PRESSURE SENSOR SIGNAL
31 - -
32 K25 20VT/DG BATTERY TEMPERATURE SENSOR SIGNAL
33 - -
34 K255 20WT/DG ACCELERATOR PEDAL POSITION SENSOR 1 GROUND
35 Y43 20WT/VT ACCELERATOR PEDAL POSITION SENSOR 1 5-VOLT
SUPPLY
36 C18 20DB A/C PRESSURE SENSOR SIGNAL
37 - -
38 V37 20RD/DG SPEED CONTROL SWITCH SIGNAL
39 K226 20DB/WT FUEL LEVEL SENSOR SIGNAL
40 K2 20DG/RD ENGINE COOLANT TEMPERATURE SENSOR SIGNAL
41 K21 20DG/WT INTAKE AIR TEMPERATURE SENSOR SIGNAL
42 Y101 20 CRANKSHAFT POSITION SENSOR SHIELD
43 K924 20YL CRANKSHAFT POSITION SENSOR SIGNAL 2
44 - -
45 - -
46 - -
47 L50 20WT/DB PRIMARY BRAKE SWITCH SIGNAL
48 K29 20WT/PK SECONDARY BRAKE SWITCH SIGNAL
49 - -
50 F855 18BR/YL SENSOR REFERENCE VOLTAGE A
51 - -
52 - -
53 - -
54 Z189 20BR MASS AIR FLOW SENSOR GROUND
WJ8W-80 CONNECTOR PIN-OUT 8W - 80 - 75

TRANSMISSION CONTROL MODULE C1 (DIESEL) - BLACK 18 WAY
CAV CIRCUIT FUNCTION
1 D21 20PK SCI TRANSMIT
2- -
3 W4 20PK/OR SHIFTER C5 SENSE
4 Y1 20DB/PK PARK LOCKOUT SOLENOID CONTROL
5- -
6- -
7 T41 20BK/WT PARK/NEUTRAL POSITION SWITCH SENSE (T41)
8- -
9- -
10 - -
23 - -
24 - -
25 W0 20DB/WT SHIFTER C1 SENSE
26 W1 20VT/WT SHIFTER C2 SENSE
27 W2 20VT SHIFTER C3 SENSE
28 W3 20BK SHIFTER C4 SENSE
29 F991 20OR/DB FUSED IGNITION SWITCH OUTPUT (RUN-START)
30 Z234 20WT GROUND
TRANSMISSION CONTROL MODULE C2 (DIESEL) - BLACK 14 WAY
CAV CIRCUIT FUNCTION
12 T52 18RD/BK N2 INPUT SPEED SENSOR
13 T39 18GY/LB SENSOR SUPPLY VOLTAGE
14 T60 18BR 1-2/4-5 SOLENOID CONTROL
15 T159 18DG/WT 3-4 SOLENOID CONTROL
16 T119 18WT/DB 2-3 SOLENOID CONTROL
17 T120 18LG TCC SOLENOID CONTROL
33 T13 18DB/BK SENSOR GROUND
34 T54 18VT TEMP SENSOR - P/N SWITCH
35 T14 18LG/WT N3 INPUT SPEED SENSOR
36 T591 18YL/DB MODULATION PRESSURE SOLENOID CONTROL
37 T118 18YL/DB SHIFT PRESSURE SOLENOID CONTROL
38 T16 18RD SOLENOID SUPPLY VOLTAGE
H1 D52 18LG/WT CAN C BUS(+)
L2 D51 18DG/WT CAN C BUS(-)
TRANSMISSION SOLENOID (4.0L) - BLACK 8 WAY
CAV CIRCUIT FUNCTION
1 T15 18LG FUSED TRANSMISSION CONTROL RELAY OUTPUT
2 K6 18VT/BK 5 VOLT SUPPLY
3 K4 18BK/LB SENSOR GROUND
4 T25 18LG/RD GOVERNOR PRESSURE SENSOR SIGNAL
5 K88 18PK GOVERNOR PRESSURE SOLENOID CONTROL
6 T60 18BR 3-4 SHIFT SOLENOID CONTROL
7 T20 18LB TORQUE CONVERTER CLUTCH SOLENOID CONTROL
8 T54 18VT TRANSMISSION TEMPERATURE SENSOR SIGNAL
WJ8W-80 CONNECTOR PIN-OUT 8W - 80 - 125

(5) Reconnect the right and left body wire harness
bulkhead connectors to the connector receptacles
located near the center of the JB.
(6) Install and tighten the screws that secure the
right and left body wire harness bulkhead connectors
to the connector receptacles located near the center
of the JB. Tighten the screws to 2.2 N´m (20 in. lbs.).
(7) Reconnect the fused B(+) and the IOD wire
harness connectors to the connector receptacles
located near the bottom of the JB.
(8) Reach behind the JB to reconnect the instru-
ment panel wire harness bulkhead connector to the
connector receptacle located near the top of the JB.
(9) Install and tighten the screw that secures the
instrument panel wire harness bulkhead connector to
the connector receptacle located near the top of the
JB. Tighten the screw to 2.2 N´m (20 in. lbs.).
(10)
Reach behind the JB to reconnect the two
instrument panel wire harness connectors to the BCM
connector receptacles located near the bottom of the JB.
(11) Install the steering column opening cover onto
the instrument panel. Refer toSteering Column
Opening Coverin Body for the location of the steer-
ing column opening cover installation procedures.
(12)
Install the fuse cover onto the bottom of the JB.
(13) Reconnect the battery negative cable.
POWER DISTRIBUTION
CENTER
DESCRIPTION
All of the electrical current distributed throughout
this vehicle is directed through the standard equip-ment Power Distribution Center (PDC) (Fig. 7). The
molded plastic PDC housing is located in the right
front corner of the engine compartment, between the
battery and the right front inner fender shield. The
PDC houses up to fifteen maxi-type cartridge fuses,
which replace all in-line fusible links. The PDC also
houses up to thirteen blade-type mini fuses, and up
to ten International Standards Organization (ISO)
relays (two standard-type and eight micro-type).
The PDC housing is secured in the engine compart-
ment at three points. Integral mounts on both sides of
the PDC housing engage and latch to stanchions that
are integral to the molded plastic battery support. The
PDC is integral to the right headlamp and dash wire
harness, which exits from the bottom of the PDC hous-
ing. The PDC housing has a molded plastic cover that
includes two integral latches at the front and pivot
hooks at the back that snap over a hinge pin on the
rear of the PDC housing. The PDC cover is easily
opened or removed for service access and has a conve-
nient fuse and relay layout map integral to the inside
surface of the cover to ensure proper component identi-
fication. A fuse puller is also stored on the inside of the
PDC cover.
The PDC cover, the PDC housing lower cover, the
PDC relay wedges, the PDC relay cassettes and the
PDC B(+) terminal stud module are available for ser-
vice replacement. The PDC main housing unit, the
fuse wedges and the bus bars cannot be repaired and
Fig. 6 Junction Block
1 - SCREW (2)
2 - DRIVER SIDE COURTESY LAMP
3 - JUNCTION BLOCK
4 - 16 WAY DATA LINK CONNECTOR
Fig. 7 Power Distribution Center Location
1 - RIGHT FENDER
2 - BATTERY
3 - POWER DISTRIBUTION CENTER
4 - COVER
WJ8W-97 POWER DISTRIBUTION 8W - 97 - 7
JUNCTION BLOCK (Continued)

are only serviced as a unit with the right headlamp
and dash wire harness. If the PDC main housing
unit, fuse wedges or the bus bars are faulty or dam-
aged, the right headlamp and dash wire harness unit
must be replaced.
OPERATION
All of the current from the battery and the generator
output enters the PDC through two cables and a single
two-holed eyelet that is secured with nuts to the two
PDC B(+) terminal studs just inside the front end of the
PDC housing. The PDC cover is unlatched and opened
to access the battery and generator output connection
B(+) terminal studs, the fuses or the relays. Internal
connection of all of the PDC circuits is accomplished by
an intricate combination of hard wiring and bus bars.
Refer toPower Distribution
in Wiring Diagrams for
the location of complete PDC circuit diagrams.
REMOVAL
The Power Distribution Center (PDC) main housing
unit, the PDC fuse wedges and the PDC bus bars can-
not be repaired and are only serviced as a unit with the
right headlamp and dash wire harness. If the PDC
main housing unit, the fuse wedges or the bus bars are
faulty or damaged, the entire PDC and right headlamp
and dash wire harness unit must be replaced.
(1)Disconnect and isolate the battery negative cable.
(2) Disconnect each of the right headlamp and
dash wire harness connectors. Refer toConnector
Locationsin Wiring Diagrams for the location of
more information on the right headlamp and dash
wire harness connector locations.
(3) Remove all of the fasteners that secure each of
the right headlamp and dash wire harness ground
eyelets to the vehicle body and chassis components.
Refer toConnector Locationsin Wiring Diagrams
for the location of more information on the ground
eyelet locations.
(4) Disengage each of the retainers that secure the
right headlamp and dash wire harness to the vehicle
body and chassis components. Refer toConnector
Locationsin Wiring Diagrams for the location of
more information on the right headlamp and dash
wire harness retainer locations.
(5) Unlatch and open the PDC cover.
(6) Remove the two nuts that secure the two-holed
eyelet of the battery wire harness PDC take outs to
the PDC B(+) terminal studs (Fig. 8).
(7) Remove the battery wire harness PDC take out
eyelet from the B(+) terminal studs.
(8) Disengage the latches on the PDC housing
mounts from the tabs on the PDC mounting stan-
chions of the battery support, and pull the PDC
housing upward to disengage the mounts from the
stanchions (Fig. 9).
Fig. 8 Power Distribution Center Connections
1 - PDC COVER
2 - NUT (2)
3 - EYELET
4 - B(+) TERMINAL STUDS
Fig. 9 Power Distribution Center Remove/Install
1 - POWER DISTRIBUTION CENTER
2 - MOUNTS
3 - STANCHIONS (3)
4 - BATTERY SUPPORT
8W - 97 - 8 8W-97 POWER DISTRIBUTIONWJ
POWER DISTRIBUTION CENTER (Continued)

(9) Remove the PDC and the right headlamp and
dash wire harness from the engine compartment as a
unit.
DISASSEMBLY
POWER DISTRIBUTION CENTER DISASSEMBLY
PDC HOUSING LOWER COVER REMOVAL
The Power Distribution Center (PDC) cover, the
PDC housing lower cover, the PDC relay wedges, the
PDC relay cassettes and the PDC B(+) terminal stud
module are available for service replacement. The
PDC cover can be simply unlatched and removed
from the PDC housing without the PDC being
removed or disassembled. Service of the remaining
PDC components requires that the PDC be removed
from its mounting and disassembled. Refer toWiring
Repairin Wiring Diagrams for the location of the
wiring repair procedures.
(1) Remove the battery from the battery support.
Refer toBattery Systemfor the location of the bat-
tery removal procedures.
(2) Unlatch and remove the cover from the PDC.
(3) Remove the two nuts that secure the two-holed
eyelet of the battery wire harness PDC take out to
the B(+) terminal studs near the front of the PDC.
(4) Remove the battery wire harness PDC take out
eyelet from the two PDC B(+) terminal studs.
(5) Disengage the latches on the PDC housing
mounts from the tabs on the PDC mounting stan-
chions on the battery support, and pull the PDC
housing upward to disengage the mounts from the
stanchions.
(6) Where the right headlamp and dash wire har-
ness exits the PDC, remove the tape that secures the
wire harness to the trough formation on the PDC
housing lower cover.
(7) Using a trim stick or another suitable wide
flat-bladed tool, gently pry the latches on each side
and the front of the PDC housing that secure the
housing lower cover to the PDC and remove the
housing lower cover (Fig. 10).
PDC B+ TERMINAL MODULE REMOVAL
The Power Distribution Center (PDC) cover, the
PDC housing lower cover, the PDC relay wedges, the
PDC relay cassettes and the PDC B(+) terminal stud
module are available for service replacement. The
PDC cover can be simply unlatched and removed
from the PDC housing without the PDC being
removed or disassembled. Service of the remaining
PDC components requires that the PDC be removed
from its mounting and disassembled. Refer toWiring
Repairin Wiring Diagrams for the location of the
wiring repair procedures.(1) Remove the PDC housing lower cover.
(2) From the top of the PDC housing, use a small
screwdriver or a terminal pick tool (Special Tool Kit
6680) to release the two latches that secure the B(+)
terminal module in the PDC.
(3) Gently and evenly press the two B(+) terminal
studs down through the bus bar in the PDC.
(4) From the bottom of the PDC housing, remove
the B(+) terminal module from the PDC.
PDC RELAY WEDGE REMOVAL
The Power Distribution Center (PDC) cover, the
PDC housing lower cover, the PDC relay wedges, the
PDC relay cassettes and the PDC B(+) terminal stud
module are available for service replacement. The
PDC cover can be simply unlatched and removed
from the PDC housing without the PDC being
removed or disassembled. Service of the remaining
PDC components requires that the PDC be removed
from its mounting and disassembled. Refer toWiring
Repairin Wiring Diagrams for the location of the
wiring repair procedures.
(1) Remove the PDC housing lower cover.
(2) Remove each of the relays from the PDC relay
wedge to be removed.
(3) From the bottom of the PDC housing, use a
small screwdriver or a terminal pick tool (Special
Fig. 10 PDC Housing Lower Cover Remove/Install -
Typical
1 - TROUGH FORMATION
2 - LATCHES (5)
3 - PDC HOUSING LOWER COVER
4 - WIRE HARNESS
WJ8W-97 POWER DISTRIBUTION 8W - 97 - 9
POWER DISTRIBUTION CENTER (Continued)

PDC LOWER COVER INSTALLATION
(1) Align the PDC housing lower cover on the bot-
tom of the PDC.
(2) Evenly press the lower cover into place until
latches are fully engaged.
(3) Where the right headlamp and dash harness
enters the PDC, tape the harness securely to the
trough formation on the PDC lower cover.
(4) Install the PDC in its mounting location on the
battery support.
(5) Install the battery wire harness over the two
PDC B+ terminal studs. Torque the nuts to 11.3 N´m
(100 in. lbs.).
(6) Install the battery. Refer to Battery System for
the procedure.
(7) Install the PDC cover.
INSTALLATION
The Power Distribution Center (PDC) main hous-
ing unit, the PDC fuse wedges and the PDC bus bars
cannot be repaired and are only serviced as a unit
with the right headlamp and dash wire harness. If
the PDC main housing unit, the fuse wedges or the
bus bars are faulty or damaged, the entire PDC and
right headlamp and dash wire harness unit must be
replaced.
(1) Position the PDC and the right headlamp and
dash wire harness unit in the engine compartment.
(2) Engage the PDC housing mounts with the
stanchions of the battery support and push the unit
downward until the mount latches fully engage the
mounting tabs on the stanchions.
(3) Install the two-holed eyelet of the battery wire
harness PDC take outs onto the two PDC B(+) termi-
nal studs.
(4) Install and tighten the nuts that secure the
eyelet of the battery wire harness PDC take outs to
the B(+) terminal studs. Tighten the nuts to 11.3
N´m (100 in. lbs.).
(5) Engage each of the retainers that secure the
right headlamp and dash wire harness to the vehicle
body and chassis components. Refer toConnector
Locationsin Wiring Diagrams for the location of
more information on the right headlamp and dash
wire harness retainer locations.
(6) Install all of the fasteners that secure each of
the right headlamp and dash wire harness ground
eyelets to the vehicle body and chassis components.
Refer toConnector Locationsin Wiring Diagrams
for the location of more information on the ground
eyelet locations.
(7) Reconnect each of the right headlamp and dash
wire harness connectors. Refer toConnector Loca-
tionsin Wiring Diagrams for the location of more
information on the right headlamp and dash wire
harness connector locations. For connectors securedwith screws, tighten the screws to 4.3 N´m (38 in.
lbs.).
(8) Reconnect the battery negative cable.
POWER OUTLET
DESCRIPTION - FRONT POWER OUTLET
An accessory power outlet is standard equipment
on this model. The power outlet is installed in the
instrument panel center lower bezel, which is located
near the bottom of the instrument panel center stack
area, below the heater and air conditioner controls.
The power outlet base is secured by a snap fit within
the center lower bezel. A hinged door with an over-
center spring flips closed to conceal and protect the
power outlet base when the power outlet is not being
used, and flips open below the center lower bezel
while the power outlet is in use.
The power outlet receptacle unit and the power
outlet door are each available for service replace-
ment.
OPERATION - FRONT POWER OUTLET
The power outlet base or receptacle shell is con-
nected to ground, and an insulated contact in the
bottom of the shell is connected to battery current.
The power outlet receives battery voltage from a fuse
in the junction block at all times.
While the power outlet is very similar to a cigar
lighter base unit, it does not include the two small
spring-clip retainers inside the bottom of the recepta-
cle shell that are used to secure the cigar lighter
heating element to the insulated contact.
DIAGNOSIS AND TESTING - POWER OUTLET
For complete circuit diagrams, refer toHorn/Ci-
gar Lighter/Power Outletin Wiring Diagrams.
WARNING: REFER TO RESTRAINTS BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
(1) Check the fused B(+) fuse in the junction block.
If OK, go to Step 2. If not OK, repair the shorted cir-
cuit or component as required and replace the faulty
fuse.
(2) Check for battery voltage at the fused B(+) fuse
in the junction block. If OK, go to Step 3. If not OK,
repair the open fused B(+) circuit to the Power Dis-
tribution Center (PDC) fuse as required.
(3) Open the power outlet door. Check for continu-
ity between the inside circumference of the power
8W - 97 - 12 8W-97 POWER DISTRIBUTIONWJ
POWER DISTRIBUTION CENTER (Continued)

²6th & 7th DigitsÐThe day of engine build (01 -
31).(1)FOR EXAMPLE:Code * 801MX12 * identifies
a 4.0 Liter (242 CID) engine with a multi-point fuel
injection system, 8.7:1 compression ratio and built on
January 12, 1998.
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
mechanical (e.g., a strange noise), or performance
(e.g., engine idles rough and stalls).
(Refer to 9 - ENGINE - DIAGNOSIS AND TEST-
ING - Preformance) or (Refer to 9 - ENGINE - DIAG-
NOSIS AND TESTING - Mechanical). Refer to 14 -
FUEL SYSTEM for 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:
²Cylinder Compression Pressure Test (Refer to 9 -
ENGINE - DIAGNOSIS AND TESTING)
²Cylinder Combustion Pressure Leakage Test
(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)
²Cylinder Head Gasket Failure Diagnosis (Refer
to 9 - ENGINE/CYLINDER HEAD - DIAGNOSIS
AND TESTING)
²Intake Manifold Leakage Diagnosis (Refer to 9 -
ENGINE/MANIFOLDS/INTAKE MANIFOLD -
DIAGNOSIS AND TESTING)
²Lash Adjuster (Tappet) Noise Diagnosis (Refer to
9 - ENGINE/ENGINE BLOCK/HYDRAULIC LIFT-
ERS (CAM IN BLOCK) - DIAGNOSIS AND TEST-
ING)
²Engine Oil Leak Inspection (Refer to 9 -
ENGINE/LUBRICATION - DIAGNOSIS AND TEST-
ING)
Fig. 1 Engine Firing Order
Fig. 2 Build Date Code Location
1 - YEAR
2 - MONTH
3-DAY
WJENGINE - 4.0L 9 - 3
ENGINE - 4.0L (Continued)