relay JEEP XJ 1995 Service And Service Manual

the following procedures to reduce the possibility of
electrostatic charge build up on the body and inad-
vertent discharge into the component. If it is not
known whether the part is ESD sensitive, assume
that it is.
(1) Always touch a known good ground before han-
dling the part. This should be repeated while han-
dling the part and more frequently after sliding
across a seat, sitting down from a standing position,
or walking a distance.
(2) Avoid touching electrical terminals of the part,
unless instructed to do so by a written diagnostic
procedure.
(3) When using a voltmeter, be sure to connect the
ground lead first.
(4) Do not remove the part from its protective pack-
ing until it is time to install the part.
(5) Before removing the part from its package,
ground the package to a known good ground on the
vehicle.
TROUBLESHOOTING TOOLS
When diagnosing a problem in an electrical circuit
there are several common tools necessary. These tools
are listed and explained below.
²Jumper Wire - This is a test wire used to connect
two points of a circuit. It can be used to bypass an
open in a circuit.
WARNING: NEVER USE A JUMPER WIRE ACROSS A
LOAD, SUCH AS A MOTOR, CONNECTED BETWEEN
A BATTERY FEED AND GROUND.
²Voltmeter - Used to check for voltage on a circuit.
Always connect the black lead to a known good
ground and the red lead to the positive side of the
circuit.
CAUTION: Most of the electrical components used
in today's vehicle are solid state. When checking
voltages in these circuits use a meter with a 10-
megohm or greater impedance.
²Ohmmeter - Used to check the resistance between
two points of a circuit. Low or no resistance in a
circuit means good continuity.CAUTION: - Most of the electrical components used
in today's vehicle are Solid State. When checking
resistance in these circuits use a meter with a 10-
megohm or greater impedance. In addition, make
sure the power is disconnected from the circuit.
Circuits that are powered up by the vehicle electrical
system can cause damage to the equipment and
provide false readings.
²Probing Tools - These tools are used for probing
terminals in connectors (Fig. 7). Select the proper size
tool from Special Tool Package 6807, and insert it into
the terminal being tested. Use the other end of the
tool to insert the meter probe.
INTERMITTENT AND POOR CONNECTIONS
Most intermittent electrical problems are caused by
faulty electrical connections or wiring. It is also pos-
sible for a sticking component or relay to cause a
problem. Before condemning a component or wiring
assembly check the following items.
²Connectors are fully seated
²Spread terminals, or terminal push out
²Terminals in the wiring assembly are fully seated
into the connector/component and locked in position
²Dirt or corrosion on the terminals. Any amount of
corrosion or dirt could cause an intermittent problem
²Damaged connector/component casing exposing the
item to dirt and moisture
²Wire insulation that has rubbed through causing a
short to ground
²Wiring broke inside of the insulation
TROUBLESHOOTING TESTS
Before beginning any tests on a vehicle's electrical
system, use the Wiring Diagrams and study the cir-
cuit. Also refer to the Troubleshooting Wiring Prob-
lems section in this section.
TESTING FOR VOLTAGE
(1) Connect the ground lead of a voltmeter to a
known good ground (Fig. 8).
Fig. 6 Electrostatic Discharge Symbol
Fig. 7 Probing Tool
8W - 4 WIRING DIAGRAMSÐGENERAL INFORMATIONJ

FUSE/FUSE BLOCK
GENERAL INFORMATION
This section covers the Fuse Block and all circuits
involved with it. For additional information on sys-
tem operation, refer to the appropriate section of the
wiring diagrams.
DIAGRAM INDEX
Component Page
ABS Control Module......................8W-10-4
ABS Warning Lamp Relay...................8W-10-2
Chime/Buzzer Module.................8W-10-2, 9, 10
Circuit Breaker Cavity 16...................8W-10-12
In-Line Circuit Breaker (Wipers)...............8W-10-5
In-Line Circuit Breaker (Stop Lamp Relay)........8W-10-12
Daytime Running Lamps Module..............8W-10-8
Fuse 1 (Fuse Block).......................8W-10-4
Fuse 2 (Fuse Block).......................8W-10-5
Fuse 3 (Fuse Block).....................8W-10-4, 8
Fuse 3 (PDC)........................8W-10-6, 12
Fuse 4 (Fuse Block).......................8W-10-7
Fuse 5 (Fuse Block).......................8W-10-5
Fuse 5 (PDC)........................8W-10-7, 10
Fuse 6 (Fuse Block).......................8W-10-4
Fuse 6 (PDC).........................8W-10-4, 8
Fuse 7 (Fuse Block)....................8W-10-4, 10
Fuse 8 (Fuse Block).......................8W-10-5
Fuse 9 (Fuse Block).......................8W-10-6
Fuse 10 (Fuse Block)......................8W-10-4
Fuse 11 (Fuse Block)......................8W-10-9
Fuse 11 (PDC)..........................8W-10-8
Fuse 12 (PDC)..........................8W-10-8
Fuse 13 (Fuse Block)......................8W-10-9
Fuse 14 (Fuse Block)......................8W-10-9
Fuse 15 (Fuse Block)......................8W-10-7
Fuse 15 (PDC)..........................8W-10-6
Fuse 17 (Fuse Block)......................8W-10-9
Fuse Block.............................8W-10-2
Headlamp Delay Module....................8W-10-9
Headlamp Switch......................8W-10-7, 10
Heated Rear Window Relay.................8W-10-10
Ignition Switch........................8W-10-4, 8
Instrument Cluster.......................8W-10-11
Overhead Console.....................8W-10-9, 11
Powertrain Control Module..................8W-10-8
Remote Keyless Entry Module................8W-10-9
J8W-10 FUSE/FUSE BLOCKÐXJ VEHICLES 8W - 10 - 1

POWER DISTRIBUTION
GENERAL INFORMATION
This section covers the Power Distribution Center
(PDC) and all circuits involved with it. For additional
information on system operation, refer to the appro-
priate section of the wiring diagrams.
DIAGRAM INDEX
Component Page
A/C Compressor Clutch Relay..............8W-11-3, 11
ABS Control Module.....................8W-11-6, 7
ABS Power Relay......................8W-11-3, 6
ABS Pump Motor Relay..................8W-11-3, 7
Automatic Shut Down Relay................8W-11-3, 9
Chime/Buzzer Module..................8W-11-10, 14
Circuit Breaker Cavity 16 (Fuse Block)..........8W-11-13
Combination Flasher......................8W-11-17
Daytime Running Lamp Module.............8W-11-5, 10
Diode D101............................8W-11-6
Engine Starter Motor Relay................8W-11-3, 4
Fuel Pump Relay.......................8W-11-3, 8
Fuse 1 (PDC)..........................8W-11-13
Fuse 3 (PDC)..........................8W-11-12
Fuse 4 (Fuse Block)......................8W-11-14
Fuse 4 (PDC)..........................8W-11-15
Fuse 5 (PDC)..........................8W-11-14
Fuse 6 (PDC)....................8W-11-4, 7, 10, 15
Fuse 7 (Fuse Block).......................8W-11-7
Fuse 7 (PDC)...........................8W-11-4
Fuse 8 (PDC)...........................8W-11-7
Fuse 9 (Fuse Block)......................8W-11-12
Fuse 9 (PDC)..........................8W-11-13
Fuse 10 (PDC)........................8W-11-6, 8
Fuse 11 (Fuse Block).....................8W-11-13
Fuse 11 (PDC).........................8W-11-10
Fuse 12 (PDC).........................8W-11-15Component Page
Fuse 13 (PDC)..........................8W-11-4
Fuse 14 (PDC)..........................8W-11-8
Fuse 15 (Fuse Block).....................8W-11-14
Fuse 15 (PDC)..........................8W-11-8
Fuse 16 (PDC).........................8W-11-12
Fuse 17 (Fuse Block).....................8W-11-10
Headlamp Delay Module.................8W-11-10, 14
Headlamp Switch........................8W-11-14
Headlamp Dimmer Switch..................8W-11-14
Horn Rear Window Relay..................8W-11-17
Horn Relay............................8W-11-17
Ignition Switch...................8W-11-4, 7, 10, 15
In-Line Circuit Breaker (Stop Lamp Relay)........8W-11-13
LCD Illumination Relay....................8W-11-17
Overhead Console.....................8W-11-10, 14
Powertrain Control Module..........8W-11-4, 5, 8, 9, 11
Power Distribution Center...................8W-11-2
Power Door Lock Relay...................8W-11-16
Power Door Unlock Relay..................8W-11-16
Radiator Fan Control Relay................8W-11-3, 11
Remote Keyless Entry Module.............8W-11-10, 12
Relay Center...........................8W-11-16
Telltale Connector (I.P. Cluster)..........8W-11-6, 10, 12
Torque Converter Clutch (TCC) Relay...........8W-11-15
Transmission Control Module...............8W-11-5, 8
J8W-11 POWER DISTRIBUTIONÐXJ VEHICLES 8W - 11 - 1

CHARGING SYSTEM
CHARGING SYSTEM
The charging system is an integral part of the bat-
tery and starting systems. Because all these systems
work in conjunction, diagnose and test them together.
Circuit A11 connects to the generator output termi-
nal and splices to fuse 1 and fuse 8 in the Power Dis-
tribution Center (PDC). Circuit A0 connects the
battery to the PDC.
Circuit Z0 provides ground for the generator. Cir-
cuit Z0 attaches to the right rear of the engine.
When the ignition switch is in either the START or
RUN positions, it connects circuit A1 from fuse 6 in
the PDC to circuit A21. Circuit A21 splices to supply
current to the coil side of the automatic shut down
(ASD) relay. The powertrain control module (PCM)
provides ground for the relay on circuit K51. Circuit
K51 connects to cavity 51 of the PCM.
When the PCM grounds the ASD relay, contacts in-
side the relay close and connect circuit A18 from fuse
14 in the PDC to circuit A142. Circuit A142 splices to
the generator field terminal.
The PCM has an internal voltage regulator that
controls generator output. The PCM controls the gen-
erator field on circuit K20. Circuit K20 connects to
PCM cavity 20.
When the engine operates and there is current in
the generator field, the generator produces a B+ volt-
age. The generator supplies B+ voltage to the battery
through the A11 and A0 circuits.
HELPFUL INFORMATION
²If the vehicle is equipped with a 2.5L engine, cir-
cuit Z0 also connects to the battery.
²Circuit A14 from fuse 2 in the PDC supplies volt-
age to the fuse block for fuse 14.
²The ignition switch also connects circuit A1 with
circuits A41, A38, and A48.
²Circuit A21 also splices to power fuse 17 in the
fuse block.
²Circuit A21 also powers the coil side of the fuel
pump relay.
²The ASD relay supplies battery voltage for the fuel
injectors, ignition coil, and the heated oxygen sensor.
The fuel pump relay powers the fuel pump module.
²Circuit K51 also provides ground for the coil side
of the fuel pump relay.
DIAGRAM INDEX
Component Page
Battery (2.5L)...........................8W-20-2
Battery (4.0L)...........................8W-20-3
PDC Fuse 1 (2.5L).......................8W-20-2
PDC Fuse 1 (4.0L).......................8W-20-3
PDC Fuse 9 (2.5L).......................8W-20-2
PDC Fuse 9 (4.0L).......................8W-20-3
Generator (2.5L).........................8W-20-2
Generator (4.0L).........................8W-20-3
Powertrain Control Module (2.5L)..............8W-20-2
Powertrain Control Module (4.0L)..............8W-20-3
J8W-20 CHARGING SYSTEMÐXJ VEHICLES 8W - 20 - 1

STARTING SYSTEM
INDEX
page page
Diagram Index............................ 1Starting System........................... 1
STARTING SYSTEM
AUTOMATIC TRANSMISSIONS
Circuit A0 from the battery is double crimped at
the positive battery post. One branch of circuit A0
(battery positive cable) connects to the engine starter
motor. The other A0 branch supplies voltage to the
bus bar in the power distribution center (PDC).
Fuse 7 in the PDC supplies battery voltage to the
contact side of the engine starter motor relay on cir-
cuit A4. When the coil side of the engine starter mo-
tor relay energizes, the contacts close and connect
circuit A4 to circuit T40. Circuit T40 supplies battery
voltage to the starter motor solenoid.
The ignition switch supplies battery voltage to the
coil side of the starter motor relay on circuit A41
when the key is moved to the START position and
the PARK/NEUTRAL position switch is closed.
Ground for the coil side of the starter motor relay is
supplied by the case grounded PARK/NEUTRAL po-
sition switch. Circuit T41 connects the coil side of the
relay to the PARK/NEUTRAL position switch.
When the starter motor relay energizes and the
contacts close, circuit T40 supplies battery voltage to
the starter motor solenoid. Circuit A0 from the bat-
tery supplies voltage to the starter motor when the
solenoid energizes.
MANUAL TRANSMISSIONS
Circuit A0 from the battery is double crimped at
the positive battery post. One branch of circuit A0
(battery positive cable) connects to the battery
starter motor. The other A0 branch supplies voltage
to the buss bar in the power distribution center
(PDC).
Fuse 7 in the PDC supplies battery voltage to the
contact side of the engine starter motor relay on cir-
cuit A4. When the coil side of the engine starter mo-
tor relay energizes, the contacts close and connect
circuit A4 to circuit T40. Circuit T40 supplies battery
voltage to the starter motor solenoid.The ignition switch supplies battery voltage to the
coil side of the starter motor relay on circuit A41
when the key is moved to the START position. Cir-
cuit Z12 provides ground for the coil side of the relay.
When the starter motor relay energizes and the
contacts close, circuit T40 supplies battery voltage to
the starter motor solenoid. Circuit A0 from the bat-
tery supplies voltage to the starter motor when the
solenoid energizes.
HELPFUL INFORMATION
²The Park/Neutral switch closes when the trans-
mission is in either the PARK or NEUTRAL posi-
tions.
²Circuit T41 also connects to cavity 30 of the pow-
ertrain control module (PCM). This input tells the
PCM the operator is starting the vehicle.
²Circuit A4 is double crimped at the contact side of
the starter motor relay. The A4 branch leaving the
relay powers fuse 13 in the PDC.
DIAGRAM INDEX
Component Page
Battery (2.5L)...........................8W-21-2
Battery (4.0L)...........................8W-21-3
Engine Starter Motor (2.5L)..................8W-21-2
Engine Starter Motor (4.0L)..................8W-21-3
Engine Starter Motor Relay (2.5L)..............8W-21-2
Engine Starter Motor Relay (4.0L)..............8W-21-3
Ignition Switch (2.5L)......................8W-21-2
Ignition Switch (4.0L)......................8W-21-3
PDC Fuse 6 (2.5L).......................8W-21-2
PDC Fuse 6 (4.0L).......................8W-21-3
PDC Fuse 7 (2.5L).......................8W-21-2
PDC Fuse 7 (4.0L).......................8W-21-3
Powertrain Control Module (2.5L)..............8W-21-2
Powertrain Control Module (4.0L)..............8W-21-3
Park/Neutral Position Switch (2.5L).............8W-21-2
Park/Neutral Position Switch (4.0L).............8W-21-3
J8W-21 STARTING SYSTEMÐXJ VEHICLES 8W - 21 - 1

FUEL/IGNITION
INDEX
page page
Automatic Shut Down (ASD) Relay............. 1
Battery Feed.............................. 1
Brake Switch Input......................... 5
Camshaft Position Sensor.................... 3
CCDBus ................................ 5
Crankshaft Position Sensor................... 3
Data Link Connector........................ 5
Diagram Index Ð2.5L Engine.................. 6
Diagram Index Ð4.0L Engine.................. 6
Engine Coolant Temperature Sensor............ 3
Extended Idle Switch....................... 5
Fuel Injectors............................. 1
Fuel Pump Module......................... 2
Fuel Pump Relay.......................... 2
Heated Oxygen Sensor...................... 3Idle Air Control (IAC) Motor................... 2
Ignition Coil.............................. 2
Ignition Switch............................ 1
Intake Air Temperature Sensor................ 4
Malfunction Indicator Lamp (MIL)............... 5
Manifold Absolute Pressure Sensor............. 4
Park/Neutral Position Switch.................. 4
Power (Device) Ground...................... 5
Power Steering Pressure Switch............... 5
Tachometer Signal......................... 5
Throttle Position Sensor..................... 4
Torque Converter Clutch (TCC) Solenoid and
Relay................................. 4
Upshift Lamp............................. 5
Vehicle Speed Sensor....................... 2
IGNITION SWITCH
Circuit A1 from fuse 11 in the power distribution
center (PDC), supplies battery voltage to the ignition
switch. Depending upon position, the ignition switch
powers circuits A21, A38, A41, or A48.
START POSITION
In the START position, the ignition switch connects
circuit A1 to circuit A41. Circuit A41 connects to the
coil side of the starter motor relay.
Additionally in the START position, the case
grounded ignition switch provides ground for the
brake lamp switch and the warning lamps in the
instrument cluster.
START OR RUN POSITION
In the START or RUN position, the ignition switch
connects circuit A1 to circuit A21. Circuit A21 splices
to power fuse 17 in the fuse block and the coil side of
the Automatic Shut Down (ASD) relay and the fuel
pump relay.
RUN (ONLY) POSITION
When the ignition switch is in the RUN position, it
connects circuit A1 to circuit A38. Circuit A22 splices
to power fuses 1 and 7 in the fuse block.
²Fuse 1 powers the rear wiper system on circuit
V15.
²Fuse 7 feeds the Anti-Lock Brake System (ABS) on
circuit 236.
ACCESSORY OR RUN POSITIONS
In the ACCESSORY or RUN positions, the ignition
switch connects circuit A1 to circuit A48. Circuit A48
connects to a bus bar in the fuse block that feeds
fuses 2, 5, and 8.
AUTOMATIC SHUT DOWN (ASD) RELAY
When the ignition switch is in either the START or
RUN positions, it connects circuit A1 from fuse 6 in
the Power Distribution Center (PDC) to circuit A21.
Circuit A21 supplies battery voltage to the coil side of
the Automatic Shut Down (ASD) relay. The Power-
train Control Module (PCM) provides ground for the
relay on circuit K51. Circuit K51 connects to cavity 51
of the PCM.
When the PCM grounds the ASD relay, contacts
inside the relay close and connect circuit A18 from
fuse 14 in the PDC to circuit A142. Circuit A142
splices to the generator field terminal, fuel injectors,
and ignition coil. Circuit A142 also connects to cavity
57 of the PCM.
HELPFUL INFORMATION
²Along with supplying voltage to the coil side of the
ASD relay, circuit A21 also supplies voltage to the coil
side of the fuel pump relay.
BATTERY FEED
Circuit A14 from fuse 2 in the Power Distribution
Center (PDC) supplies battery voltage to cavity 3 of
the powertrain control module.
HELPFUL INFORMATION
Circuit A14 also supplies power to the contact sides
of the fuel pump relay and fuse F2 in the PDC. Fuse
F2 powers circuit A18 which supplies voltage to the
contact side of the automatic shut down relay.
FUEL INJECTORS
When the Automatic Shut Down (ASD) relay con-
tacts close, they connect circuits A14 and A142. Cir-
J8W-30 FUEL/IGNITIONÐXJ VEHICLES 8W - 30 - 1

cuit A142 supplies voltage to the fuel injectors. Each
injector has a separate ground circuit controlled by
the PCM.
Circuit K11 provides ground for injector number
one. The K11 circuit connects to cavity 16 of the
PCM.
Circuit K12 provides ground for injector number
two. The K12 circuit connects to cavity 15 of the
PCM.
Circuit K13 provides ground for injector number
three. The K13 circuit connects to cavity 14 of the
PCM.
Circuit K14 provides ground for injector number
four. The K14 circuit connects to cavity 13 of the
PCM.
On the 4.0L engine, circuit K15 provides ground for
injector number five. The K15 circuit connects to cav-
ity 38 of the PCM.
Also on the 4.0L engine, circuit K16 provides
ground for injector number six. The K16 circuit con-
nects to cavity 58 of the PCM.
HELPFUL INFORMATION
²Circuit A142 splices to supply voltage to the fuel
injectors, ignition coil, PCM, generator.
²For information about fuel injector operation, refer
to Group 14.
IGNITION COIL
When the Automatic Shut Down (ASD) relay con-
tacts close, they connect circuits A14 and A142. Cir-
cuit A142 supplies voltage to the fuel injectors.
Circuit A142 splices to supply voltage to the ignition
coil. The PCM controls the ground path for the igni-
tion coil on circuit K19. Circuit K19 connects to cav-
ity 19 of the PCM.
HELPFUL INFORMATION
Circuit A142 splices to supply voltage to the fuel
injectors, ignition coil, PCM, and generator.
FUEL PUMP RELAY
When the ignition switch is in either the START or
RUN positions, it connects circuit A1 from fuse 6 in
the Power Distribution Center (PDC) to circuit A21.
Circuit A21 supplies battery voltage to the coil side of
the fuel pump relay. The Powertrain Control Module
(PCM) provides ground for the relay on circuit K51.
Circuit K51 connects to cavity 51 of the PCM.
When the PCM grounds the fuel pump relay, con-
tacts inside the relay close and connect circuit A14
from fuse 2 in the PDC to circuit A141. Circuit A141
supplies voltage to the fuel pump motor (part of the
in-tank fuel pump module).
HELPFUL INFORMATION
²Circuit A14 also splices to supply battery voltage
to cavity 3 of the PCM.²Circuit A141 also supplies battery voltage to the
heated oxygen sensor.
FUEL PUMP MODULE
FUEL PUMP MOTOR
When the fuel pump relay contacts close, the relay
supplies voltage to the fuel pump motor. Circuit A141
from the relay supplies voltage to circuit A241. Cir-
cuit A241 connects to circuit F9 in the fuel pump
module harness. Circuit F9 connects to the fuel pump
motor.
Circuit 99 in the fuel pump module harness con-
nects to circuit Z1. Circuit Z1 provides ground for the
fuel pump motor.
FUEL LEVEL SENSOR
The fuel level sensor is a variable resistor. Circuit
G4 connects the fuel level sensor to the fuel gauge in
the instrument cluster. Circuit F87 from fuse 17 in
the fuse block supplies voltage to the fuel gauge. The
fuel level sensor draws voltage from circuit F87
through the fuel gauge on circuit G4. Circuit G4 con-
nects to circuit 57 in the fuel pump module harness.
Circuit 57 connects to the fuel level sensor.
Circuit 99 in the fuel pump module harness con-
nects to circuit Z1. Circuit Z1 provides the ground
path for the fuel level sensor. The grounding point for
circuit Z1 is the left side of the cowl panel.
HELPFUL INFORMATION
As current flows through the coils in the fuel
gauge, it creates a magnetic field. One of the coils in
the gauge receives fixed current. The other coil is
connected to the level sensor. The magnetic field con-
trols the position of the fuel gauge pointer.
The fuel level sensor contains a variable resistor.
As the position of the float arm on the fuel level sen-
sor changes, the resistor changes the current flow
through second coil in the fuel gauge. A change in
current flow alters the magnetic field in the fuel
gauge, which changes the pointer position.
IDLE AIR CONTROL (IAC) MOTOR
The Powertrain Control Module (PCM) operates
the idle air control motor through 4 circuits - K39,
K40, K59, and K60. Each circuit connects to separate
cavities in the PCM connector.
²Circuit K39 connects to cavity 39 of the PCM
²Circuit K40 connects to cavity 40 of the PCM
²Circuit K59 connects to cavity 59 of the PCM
²Circuit K60 connects to cavity 60 of the PCM
VEHICLE SPEED SENSOR
Circuit K7 supplies 8 volts from the Powertrain
Control Module (PCM) to the vehicle speed sensor.
The K7 circuit connects to cavity 7 of the PCM.
8W - 30 - 2 8W-30 FUEL/IGNITIONÐXJ VEHICLESJ

Circuit G7 from the vehicle speed sensor provides
an input signal to the PCM. The G7 circuit connects
to cavity 47 of the PCM.
The PCM provides a ground for the vehicle speed
sensor signal (circuit G7) through circuit K4. Circuit
K4 connects to cavity 4 of the PCM.
HELPFUL INFORMATION
²Circuit G7 splices to the speedometer, and daytime
running lights module (DRL).
²Circuit K7 splices to supply 8 volts to the camshaft
position sensor and crankshaft position sensor.
Circuit K4 splices to supply ground for the signals
from the following:
²Heated oxygen sensor
²Camshaft position sensor
²Crankshaft position sensor
²Throttle position sensor
²Manifold absolute pressure sensor
²Engine coolant temperature sensor
²Intake air temperature sensor
HEATED OXYGEN SENSOR
When the fuel pump relay contacts close, they con-
nect circuits A14 and A141. Circuit A141 splices to
supply voltage to the heated oxygen sensor.
Circuit K41 delivers the signal from the heated ox-
ygen sensor to the PCM. Circuit K41 connects to cav-
ity 41 of the PCM.
The PCM provides a ground for the heated oxygen
sensor signal (circuit K41) through circuit K4. Circuit
K4 connects to cavity 4 of the PCM connector.
Circuit Z12 provides a ground for the heater circuit
in the sensor.
Circuit Z12 terminates at the right side of the en-
gine.
HELPFUL INFORMATION
²Circuit A141 also supplies battery voltage to the
fuel pump.
Circuit K4 splices to supply ground for the signals
from the following:
²Heated oxygen sensor
²Camshaft position sensor
²Crankshaft position sensor
²Intake air temperature sensor
²Throttle position sensor
²Manifold absolute pressure sensor
²Engine coolant temperature sensor
²Vehicle speed sensor
CAMSHAFT POSITION SENSOR
The Powertrain Control Module (PCM) supplies 8
volts to the camshaft position sensor (in distributor)
on circuit K7. Circuit K7 connects to cavity 7 of the
PCM.The PCM receives the camshaft position sensor sig-
nal on circuit K44. Circuit K44 connects to cavity 44
of the PCM.
The PCM provides a ground for the camshaft posi-
tion sensor signal (circuit K44) through circuit K4.
Circuit K4 connects to cavity 4 of the PCM.
HELPFUL INFORMATION
²Circuit K7 splices to supply 8 volts to the crank-
shaft position sensor and the vehicle speed sensor.
Circuit K4 splices to supply ground for the signals
from the following:
²Heated oxygen sensor
²Camshaft position sensor
²Crankshaft position sensor
²Intake air temperature sensor
²Throttle position sensor
²Manifold absolute pressure sensor
²Engine coolant temperature sensor
²Vehicle speed sensor
CRANKSHAFT POSITION SENSOR
The Powertrain Control Module (PCM) supplies 8
volts to the crankshaft position sensor on circuit K7.
Circuit K7 connects to cavity 7 of the PCM.
The PCM receives the crankshaft position sensor
signal on circuit K24. Circuit K24 connects to cavity
24 of the PCM.
The PCM provides a ground for the crankshaft po-
sition sensor (circuit K24) through circuit K4. Circuit
K4 connects to cavity 4 of the PCM.
HELPFUL INFORMATION
²Circuit K7 splices to supply 8 volts to the camshaft
position sensor and the vehicle speed sensor.
Circuit K4 splices to supply ground for the signals
from the following:
²Heated oxygen sensor
²Camshaft position sensor
²Crankshaft position sensor
²Intake air temperature sensor
²Throttle position sensor
²Manifold absolute pressure sensor
²Engine coolant temperature sensor
²Vehicle speed sensor
ENGINE COOLANT TEMPERATURE SENSOR
The engine coolant temperature sensor provides an
input to the Powertrain Control Module (PCM) on
circuit K2. From circuit K2, the engine coolant tem-
perature sensor draws up to 5 volts from the PCM.
The sensor is a variable resistor. As coolant temper-
ature changes, the resistance in the sensor changes,
causing a change in current draw. The K2 circuit
connects to cavity 2 of the PCM.
J8W-30 FUEL/IGNITIONÐXJ VEHICLES 8W - 30 - 3

The PCM provides a ground for the engine coolant
temperature sensor signal (circuit K2) through circuit
K4. Circuit K4 connects to cavity 4 of the PCM con-
nector.
HELPFUL INFORMATION
Circuit K4 splices to supply ground for the signals
from the following:
²Heated oxygen sensor
²Camshaft position sensor
²Crankshaft position sensor
²Intake air temperature sensor
²Throttle position sensor
²Manifold absolute pressure sensor
²Engine coolant temperature sensor
²Vehicle speed sensor
THROTTLE POSITION SENSOR
From the Powertrain Control Module (PCM), cir-
cuit K6 supplies 5 volts to the throttle position sen-
sor (TPS). Circuit K6 connects to cavity 6 of the
PCM.
Circuit K22 delivers the TPS signal to the PCM.
Circuit K22 connects to cavity 22 of the PCM.
The PCM provides a ground for the throttle posi-
tion sensor signal (circuit K22) through circuit K4.
Circuit K4 connects to cavity 4 of the PCM.
HELPFUL INFORMATION
Refer to Group 14 for throttle position sensor oper-
ation.
Circuit K6 splices to supply 5 volts to the manifold
absolute pressure sensor.
On vehicles equipped with the 4.0L engine and au-
tomatic transmission, circuit K22 splices to the
transmission control module.
Circuit K4 splices to supply ground for the signals
from the following:
²Heated oxygen sensor
²Camshaft position sensor
²Crankshaft position sensor
²Intake air temperature sensor
²Throttle position sensor
²Manifold absolute pressure sensor
²Engine coolant temperature sensor
²Vehicle speed sensor
MANIFOLD ABSOLUTE PRESSURE SENSOR
From the Powertrain Control Module (PCM), cir-
cuit K6 supplies 5 volts to the manifold absolute
pressure (MAP) sensor. Circuit K6 connects to cavity
6 of the PCM.
Circuit K1 delivers the MAP signal to the PCM.
Circuit K1 connects to cavity 1 of the PCM.
The PCM provides a ground for the MAP sensor
signal (circuit K1) through circuit K4. Circuit K4 con-
nects to cavity 4 of the PCM.
HELPFUL INFORMATION
Refer to Group 14 for MAP sensor operation.
Circuit K6 splices to supply 5 volts to the throttle
position sensor.
Circuit K4 splices to supply ground for the signals
from the following:
²Heated oxygen sensor
²Camshaft position sensor
²Crankshaft position sensor
²Intake air temperature sensor
²Throttle position sensor
²Manifold absolute pressure sensor
²Engine coolant temperature sensor
²Vehicle speed sensor
INTAKE AIR TEMPERATURE SENSOR
The intake air temperature sensor provides an in-
put to the Powertrain Control Module (PCM) on cir-
cuit K21. Circuit K21 connects to cavity 21 of the
PCM.
From circuit K21, the intake air temperature sen-
sor draws voltage from the PCM. The sensor is a
variable resistor. As intake air temperature changes,
the resistance in the sensor changes, causing a
change in current draw.
The PCM provides a ground for the intake air tem-
perature sensor signal (circuit K21) through circuit
K4. Circuit K4 connects to cavity 4 of the PCM.
HELPFUL INFORMATION
Circuit K4 splices to supply ground for the signals
from the following:
²Heated oxygen sensor
²Camshaft position sensor
²Crankshaft position sensor
²Intake air temperature sensor
²Throttle position sensor
²Manifold absolute pressure sensor
²Engine coolant temperature sensor
²Vehicle speed sensor
PARK/NEUTRAL POSITION SWITCH
When closed, the case-grounded park/neutral posi-
tion switch provides a ground path on circuit T41 for
the coil side of the starter motor relay. Circuit A41
from the ignition switch provides battery voltage to
the coil side of the relay.
Circuit T41 splices to cavity 30 of the PCM. The
park/neutral position switch provides an input to the
Powertrain Control Module (PCM).
TORQUE CONVERTER CLUTCH (TCC) SOLENOID
AND RELAY
The TCC solenoid is only used on 2.5L engines
with the three-speed automatic transmissions. The
Powertrain Control Module (PCM) operates the TCC
solenoid by energizing the TCC relay.
8W - 30 - 4 8W-30 FUEL/IGNITIONÐXJ VEHICLESJ

Circuit T17 from fuse 3 in the power distribution
center supplies voltage to the coil and contact sides
of the TCC relay. When the PCM provides a ground
path on circuit K54 for the coil side of the relay, the
relay contacts close.
When the relay contacts close, they connect circuit
T17 with circuit T22. Circuit T22 supplies battery
voltage to the case grounded TCC solenoid. Circuit
K54 connects to PCM cavity 54.
HELPFUL INFORMATION
²In the RUN or START position, the ignition switch
connects circuit A1 from fuse 4 in the PDC to circuit
A21.
UPSHIFT LAMP
On vehicles equipped with a manual transmission,
the PCM grounds the up-shift lamp on circuit K54.
Circuit K54 connects to cavity 54 of the PCM.
POWER STEERING PRESSURE SWITCH
The PCM supplies voltage to the power steering
pressure switch on circuit K10. Circuit Z12 provides
ground for the switch. When the switch closes, volt-
age flows through the switch to ground on circuit
Z12. The switch closes during periods of high power
steering pump load and low engine speed; such as
parking maneuvers.
Circuit K10 connects to cavity 10 of the PCM. Cir-
cuit Z12 terminates at the right rear of the engine.
TACHOMETER SIGNAL
The PCM supplies the signal for the tachometer on
circuit G21. Circuit G21 connects to cavity 43 of the
PCM.
MALFUNCTION INDICATOR LAMP (MIL)
The PCM provides ground for the instrument clus-
ter malfunction indicator lamp on circuit G3. The
MIL displays the message CHECK ENGINE when il-
luminated. Circuit F87 provides voltage for the lamp.
DATA LINK CONNECTOR
Circuit F12 supplies battery voltage to the data
link connector. Circuit F12 originates at fuse 11 in
the Power Distribution Center.
Circuit D20 connects to cavity 45 of the PCM. Cir-
cuit D20 is the SCI receive circuit for the PCM.
Circuit D21 connects to cavity 25 of the PCM. Cir-
cuit D21 is the SCI transmit circuit for the PCM.
Circuit Z11 provides ground for the data link con-
nector. Circuit Z11 terminates at the right rear of the
engine. Circuit Z11 also connects to cavity 5 of the
PCM.
HELPFUL INFORMATION
²Circuit Z1 also supplies a ground for the PCM
high current drivers.
²If the system loses ground for the Z11 circuits at
the right rear of the engine, the vehicle will not op-
erate. Check the connection at the ganged-ground cir-
cuit eyelet.
²Circuit F12 splices to supply battery voltage to the
vehicle speed control switch, back-up lamp switch,
A/C compressor clutch relay, windshield washer fluid
level sensor and radiator fan relay (4.0L engines).
BRAKE SWITCH INPUT
Circuit K29 provides the brake switch input to the
PCM. Circuit V40 connects to cavity 29 of the PCM.
POWER (DEVICE) GROUND
Circuit Z12 connects to cavities 11 and 12 of the
PCM. The Z12 circuit provides ground for PCM inter-
nal drivers that operate high current devices like the
injectors and ignition coil.
Internal to the PCM, the power (device) ground cir-
cuit connects to the PCM sensor return circuit (from
circuit K4).
HELPFUL INFORMATION
²The grounding point for circuit Z12 is the right
rear of the engine.
²If the system loses ground for the Z12 circuits at
the rear of the engine, the vehicle will not operate.
Check the connection at the ganged-ground circuit
eyelet.
²On vehicles equipped with the 4.0L engine and au-
tomatic transmission, circuit Z12 splices to provide
ground for the transmission control module.
EXTENDED IDLE SWITCH
On Police Package vehicles, an optional extended
idle switch provides an input to the Powertrain Con-
trol Module (PCM) on circuit K10. Circuit K10 con-
nects to cavity 10 of the PCM. Circuit F60 supplies
battery voltage to the extended idle switch. Circuit
Z1 grounds the switch.
CCD BUS
On vehicles equipped with the 4.0L engine, circuits
D1 and D2 connect the Powertrain Control Module
(PCM) to the CCD Bus. Circuit D1 connects to cavity
26 of the PCM. Circuit D2 connects to cavity 46 of
the PCM. Circuits D1 and D2 are a twisted pair of
wires.
J8W-30 FUEL/IGNITIONÐXJ VEHICLES 8W - 30 - 5