1995 JEEP YJ engine coolant

FUEL/IGNITION
INDEX
page page
Automatic Shut Down (ASD) Relay............. 1
Battery Feed.............................. 1
Brake Switch Input......................... 5
Camshaft Position Sensor.................... 3
Crankshaft Position Sensor................... 3
Data Link Connector........................ 4
Diagram Index............................ 5
Engine Coolant Temperature Sensor............ 3
Fuel Injectors............................. 1
Fuel Pump Module......................... 2
Fuel Pump Relay.......................... 2
Heated Oxygen Sensor...................... 3Idle Air Control (IAC) Motor................... 2
Ignition Coil.............................. 2
Ignition Feed............................. 1
Ignition Switch............................ 1
Intake Air Temperature Sensor................ 4
Malfunction Indicator Lamp (MIL)............... 4
Manifold Absolute Pressure Sensor............. 4
Park/Neutral Position Switch.................. 4
Power (Device) Ground...................... 5
Tachometer Signal......................... 4
Throttle Position Sensor..................... 4
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 in-
strument 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 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 A38 feeds
circuit L39.
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.
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 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, fuel injectors, and igni-
tion 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.
²Circuit A21 also connects to cavity 9 of the PCM.
BATTERY FEED
Circuit A14 from fuse 2 in the power distribution
center supplies battery voltage to cavity 3 of the
Powertrain Control Module (PCM).
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.
IGNITION FEED
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 also connects to cavity 9 of the PCM and
provides the ignition input.
FUEL INJECTORS
When the Automatic Shut Down (ASD) relay con-
tacts close, they connect circuits A18 and A142. Cir-
J8W-30 FUEL/IGNITIONÐXJ-RHD 8W - 30 - 1

HELPFUL INFORMATION
²Circuit G7 splices to the speedometer.
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.
HELPFUL INFORMATION
²Circuit A141 also supplies battery voltage to the
fuel pump.
Circuit K4 splices to supply ground for the signals
from the following:
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 sensor²Crankshaft 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
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 temperature sen-
sor draws up to 5 volts from the PCM. The sensor is
a variable resistor. As coolant temperature changes,
the resistance in the sensor changes, causing a
change in current draw. The K2 circuit connects to
cavity 2 of the PCM.
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
²Vehicle speed sensor
J8W-30 FUEL/IGNITIONÐXJ-RHD 8W - 30 - 3

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.
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
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
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
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).
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 Powertrain Control Module (PCM) provides
ground for the instrument cluster malfunction indica-
tor lamp on circuit G3. The MIL displays the mes-
sage CHECK ENGINE when illuminated. Circuit
F87 provides voltage for the lamp. Circuit G3 con-
nects to cavity 32 of the PCM.
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 also connects to cavity 5 of the
PCM.
8W - 30 - 4 8W-30 FUEL/IGNITIONÐXJ-RHDJ

HELPFUL INFORMATION
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.
BRAKE SWITCH INPUT
Circuit K29 provides the brake switch input to the
PCM. Circuit K29 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.
DIAGRAM INDEX
Component Page
Automatic Shut Down Relay.................8W-30-6
Camshaft Position Sensor...................8W-30-8
Crankshaft Position Sensor..................8W-30-9
Data Link Connector......................8W-30-11
Distributor Ignition Coil....................8W-30-11
Engine Coolant Temperature Sensor.............8W-30-9
Fuel Injector #1.........................8W-30-7
Fuel Injector #2.........................8W-30-7
Fuel Injector #3.........................8W-30-7
Fuel Injector #4.........................8W-30-7
Fuel Injector #5.........................8W-30-7
Fuel Injector #6.........................8W-30-7
Fuel Pump Relay........................8W-30-12
Fuel Tank Gauge Level Sending Unit...........8W-30-12
Fuse 2 (PDC)...........................8W-30-6
Fuse 6 (PDC)...........................8W-30-6
Fuse 11 (PDC).......................8W-30-6, 11
Fuse 14 (PDC)..........................8W-30-6
Heated Oxygen Sensor....................8W-30-10
Idle Air Control Motor.....................8W-30-10
Ignition Switch.......................8W-30-6, 12
Instrument Cluster....................8W-30-11, 12
Intake Air Temperature Sensor................8W-30-9
MAP Sensor............................8W-30-8
Powertrain Control Module.............8W-30-6 thru 12
Throttle Position Sensor....................8W-30-8
Vehicle Speed Sensor.....................8W-30-11
J8W-30 FUEL/IGNITIONÐXJ-RHD 8W - 30 - 5

DIAGRAM INDEX
Component Page
4WD Switch.........................8W-40-9, 13
4WD Indicator Lamp....................8W-40-9, 13
ABS Control Module...................8W-40-10, 13
Brake Warning Switch...................8W-40-9, 14
Chime/Buzzer Module...................8W-40-8, 12
Dimming Module........................8W-40-11
Diode...............................8W-40-13
Engine Coolant Temperature Sending Unit.........8W-40-6
Engine Oil Pressure Sending Unit..............8W-40-6
Fuse 5 (PDC)........................8W-40-4, 11
Fuse 6 (PDC)......................8W-40-4, 8, 12
Fuse 11 (PDC).......................8W-40-8, 12
Fuse 9 (Fuse Block)....................8W-40-4, 11
Fuse 25 (Fuse Block)...................8W-40-4, 11Component Page
Fuse 26 (Fuse Block).................8W-40-4, 8, 12
Fog Lamp Switch Lamp...................8W-40-11
Headlamp Switch......................8W-40-4, 11
Headlamp Delay Module.................8W-40-8, 12
Headlamp Dimmer Switch...................8W-40-5
Ignition Switch.................8W-40-4, 6, 8, 12, 14
Instrument Cluster................8W-40-4 thru 7, 14
Low Washer Fluid Lamp Switch............8W-40-8, 12
Overhead Console.....................8W-40-8, 12
Park Brake Switch.....................8W-40-9, 14
Powertrain Control Module..............8W-40-6, 9, 14
Telltale Connector (Instrument Cluster).....8W-40-8 thru 14
J8W-40 INSTRUMENT CLUSTERÐXJ-RHD 8W - 40 - 3

FUEL/IGNITION
INDEX
page page
Automatic Shut Down (ASD) Relay............. 1
Battery Feed.............................. 2
Brake Switch Input......................... 5
Camshaft Position Sensor.................... 3
Crankshaft Position Sensor................... 3
Data Link Connector........................ 5
Diagram Index............................ 5
Engine Coolant Temperature Sensor............ 3
Fuel Injectors............................. 2
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............... 4
Tachometer Signal......................... 5
Throttle Position Sensor..................... 4
Vehicle Speed Sensor....................... 3
IGNITION SWITCH
Circuit A1 from fuse 4 in the Power Distribution
Center (PDC), supplies battery voltage to the ignition
switch. Depending upon position, the ignition switch
powers circuits A21, A22, A31, and A41.
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.
Also in the START position, the case grounded ig-
nition switch provides ground for the brake lamp
switch and parking brake lamp switch on circuit G11.
START OR RUN POSITION
In the START and RUN position, the ignition
switch connects circuit A1 with circuit A21. The A21
circuit connects to fuses 5 and 9 in the fuse block.
Fuse 9 powers circuit G5. Fuse 5 powers circuit G50.
²Circuit G5 powers the buzzer module. Circuit G5
also splices to power the daytime running lamps
module (Canada only), A/C compressor clutch relay,
heated rear window relay, and the gauges and indi-
cator lamps in the instrument cluster.
RUN (ONLY) POSITION
When the ignition switch is in the RUN position, it
connects circuit A1 to circuit A22. Circuit A22 powers
fuses 1, 12, and 13 in the fuse block.
²Fuse 1 powers the rear wiper system on circuit
V23.
²Fuse 12 feeds the blower motor and air condition-
ing system on circuit C1.
²Fuse 13 feeds circuit F15 which powers the ABS
module and connects to the coil side of the ABS
power relay.
ACCESSORY OR RUN POSITION
In the ACCESSORY or RUN position, the ignition
switch connects circuit A1 to circuit A31. Circuit A31
connects to a bus bar in the fuse block that feeds
fuses 4 and 7 along with the circuit breaker in cavity
11 .
²Fuse 4 powers circuit L5 which feeds the turn sig-
nal flasher.
²Fuse 7 powers circuit F30. Circuit F30 supplies
power to the radio, radio relay, and the cigar lighter.
²The circuit breaker in cavity 11 powers the V6 cir-
cuits which feed the wiper switch and wiper motor.
AUTOMATIC SHUT DOWN (ASD) RELAY
When the ignition switch is in either the START or
RUN position, it connects circuit A1 from fuse 4 in
the Power Distribution Center (PDC) to circuit A21.
Circuit A21 powers fuse 5 in the fuse block. Circuit
G50 from fuse 5 splices to power 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 A14 from fuse
1 in the PDC to circuit A142. Circuit A142 splices to
the generator field terminal, fuel injectors, ignition
coil, and heated oxygen sensor. Circuit A142 also con-
nects to cavity 57 of the PCM.
Circuit A14 from fuse 1 in the PDC supplies bat-
tery voltage to the contact side of the ASD relay.
HELPFUL INFORMATION
²Along with supplying voltage to the ASD relay
contacts, circuit A14 supplies voltage to the contact
side of the fuel pump relay.
²Circuit G50 also supplies battery voltage to the
coil side of the fuel pump relay.
²Circuit A14 also connects to cavity 3 of the PCM.
J8W-30 FUEL/IGNITIONÐYJ VEHICLES 8W - 30 - 1

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.
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 Day-
time Running Lamp 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 Automatic Shut Down (ASD) relay con-
tacts close, they connect circuits A14 and A142. Cir-
cuit A142 splices to supply voltage to the heated
oxygen sensor.
Circuit K41 delivers the signal from the heated ox-
ygen sensor to the Powertrain Control Module
(PCM). Circuit K41 connects to cavity 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 Z1 provides a ground for the heater circuit
in the sensor. Circuit Z1 terminates at the rear of the
engine.
HELPFUL INFORMATION
²Along with supplying voltage to the ASD relay
contacts, circuit A14 supplies voltage to the contact
side of the fuel pump relay.
²Circuit A142 splices to supply voltage to the fuel
injectors, ignition coil, and heated oxygen sensor.
Circuit K4 splices to supply ground for the signals
from the following:
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
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 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
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/IGNITIONÐYJ 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
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 (MAP) 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
²Manifold absolute pressure sensor
²Engine coolant temperature sensor
²Vehicle speed sensor
MANIFOLD ABSOLUTE PRESSURE (MAP) 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
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
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 Powertrain
Control Module (PCM). The park/neutral position
switch provides an input to the (PCM).
HELPFUL INFORMATION
²In the START position, the ignition switch con-
nects circuit A1 from the Power Distribution Center
(PDC) to circuit A41. Fuse 4 in the fuse block pro-
tects circuits A1 and A41.
²The Park/Neutral position switch and back-up
lamp switch are molded together.
POWER STEERING PRESSURE SWITCH
The Powertrain Control Module (PCM) supplies
voltage to the power steering pressure switch on cir-
cuit K10. Circuit Z1 provides ground for the switch.
When the switch closes, voltage flows through the
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