1995 JEEP CHEROKEE abs sensor

ANTI-LOCK BRAKES
GENERAL INFORMATION
Three fuses supply power for the Anti-Lock Brake
System (ABS); fuses 9 and 10 in the PDC and fuse
13 in the fuse block. Fuses 9 and 10 in the Power
Distribution Center (PDC) are connected directly to
battery voltage and are HOT all times. Fuse 13 is
HOT when the ignition switch is the RUN position.
In the RUN position, the ignition switch connects
circuit A1 from fuse 4 in the PDC with circuit A22.
Circuit A22 connects to a bus bar in the fuse block.
The bus bar feeds circuit F15 through fuse 13. Fuse
13 is a 2 amp fuse.
Circuit F15 splices to the coil side of the ABS
power relay and cavity 53 of the ABS control module.
Circuit Z1 provides ground for the ABS control
module. Circuit Z1 connects to cavities 1 and 19 of
the ABS control module.
Refer to group 5, Brakes for operational descrip-
tions of ABS system components.
WHEEL SPEED SENSORS
The all wheel anti-lock system uses four wheel
speed sensors; one for each wheel. Each sensor con-
verts wheel speed into an electrical signal that it
transmits to the ABS control module. A pair of
twisted wires connect to each sensor to provide sig-
nals to the ABS control module.
Circuits B6 and B7 provide signals to ABS control
module from the right front wheel speed sensor. Cir-
cuit B6, which provides the LOW signal, connects to
cavity 29 of the ABS control module. Circuit B7 con-
nects to cavity 47 of the module and provides the
HIGH signal.
Circuits B8 and B9 provide signals to ABS control
module from the left front wheel speed sensor. Cir-
cuit B8, which provides the LOW signal, connects to
cavity 30 of the ABS control module. Circuit B9 con-
nects to cavity 48 of the module and provides the
HIGH signal.
Circuits B1 and B2 provide signals to ABS control
module from the right rear wheel speed sensor. Cir-
cuit B1 which provides the LOW signal, connects to
cavity 27 of the ABS control module. Circuit B2 con-
nects to cavity 45 of the module and provides the
HIGH signal.
Circuits B4 and B3 provide signals to ABS control
module from the left rear wheel speed sensor. Circuit
B3, which provides the LOW signal, connects to cav-
ity 28 of the ABS control module. Circuit B4 connects
to cavity 46 of the module and provides the HIGH
signal.
ACCELERATION SWITCH
During four-wheel drive operation, the acceleration
switch provides deceleration data to the ABS control
module. Refer to Group 5, Brakes for additional in-
formation.
Circuits B21, B22, and B23 connect the accelera-
tion sensor to the ABS control module. Circuits B21
and B22 provide switch states while circuit B23 pro-
vides ground. At the ABS control module circuit B21
connects to cavity 25, circuit B22 connects to cavity
43 and circuit B23 connects to cavity 26.
ABS POWER RELAY
The ABS power relay is located in the Power Dis-
tribution Center (PDC). When the ABS module
grounds the ABS power relay on circuit B20, the re-
lay switches to connect circuit B15 and circuit A20
from PDC fuse 10. Circuit F15 from fuse 13 in the
fuse block splices to feed the coil side of the ABS
power relay. Circuit B20 connects to cavity 34 of the
ABS control module.
Circuit B15 is double crimped at the ABS power re-
lay. One branch of circuit B15 supplies power to the
coil side of the ABS pump motor relay. The other
branch of circuit B15 splices to cavities 3 and 33 of
the ABS control module and to the hydraulic control
unit.
ABS PUMP MOTOR RELAY
The ABS pump motor relay in the Power Distribu-
tion Center (PDC) supplies voltage to the ABS pump
motor. When the ABS power relay energizes, circuit
B15 supplies battery voltage to the coil side of the
ABS pump motor relay. The ABS control module pro-
vides ground for the relay on circuit B116. Circuit
B116 connects to cavity 15 of the ABS control mod-
ule.
When the ABS pump motor energizes, it connects
circuit A10 from PDC fuse 9 to circuit B25. Circuit
B25 supplies battery voltage to the pump motor. Cir-
cuit Z12 provides ground for the pump motor.
PUMP MOTOR SPEED SENSOR
The input from the pump motor speed sensor tells
the ABS control module that the pump is operating.
Circuit B17 and B16 from the control module connect
to the speed sensor.
BRAKE PEDAL TRAVEL SENSOR
The brake pedal travel sensor provides the ABS
control module with data regarding brake pedal posi-
tion. The sensor is a variable resistor that the ABS
J8W-32 ANTI-LOCK BRAKESÐYJ VEHICLES 8W - 32 - 1

module provides voltage to and receives input from.
Circuit B210 from cavity 41 of the ABS control mod-
ule provides voltage to the sensor. Circuit B258 car-
ries the signal from the sensor to cavity 16 of the
ABS module.
BRAKE SWITCH INPUT
Circuit L50 from the stop lamp provides the brake
switch input to the ABS control module. When the
brake pedal is pressed, the stop lamp switch closes to
supply battery voltage from circuit F32 to circuit
L50. Circuit L50 connects to cavity 32 of the ABS
control module. Circuit F32 originates at fuse 3 in
the fuse block.
Circuit A6 from Power Distribution Center (PDC)
fuse 3 supplies voltage to the fuse block for circuit
F32.
HYDRAULIC CONTROL UNIT
When the ABS power relay energizes, two branches
of circuit B15 splice to supply voltage to the isolation
and decay solenoids in the hydraulic control unit.
The hydraulic control unit contains three separate
isolation solenoids and three separate decay sole-
noids. The ABS control module activates the decay
and isolation solenoids by providing separate ground
paths for each.
The ABS module provides a ground path for the
rear isolation solenoid on circuit B251. Circuit B251
connects to cavity 54 of the ABS control module.
For the right front isolation solenoid, the ABS mod-
ule provides a ground path on circuit B249. Circuit
B249 connects to cavity 38 of the ABS control mod-
ule.
On circuit B245, the ABS module provides ground
for the left front isolation solenoid. Circuit B245 con-
nects to cavity 20 of the ABS control module.
The ABS module provides a ground path for the
rear decay solenoid on circuit B254. Circuit B254
connects to cavity 36 of the ABS control module.
For the right front decay solenoid, the ABS module
provides a ground path on circuit B248. Circuit B248
connects to cavity 21 of the ABS control module.
On circuit B243, the ABS module provides ground
for the left decay solenoid. Circuit B243 connects to
cavity 2 of the ABS control module.
ABS WARNING LAMP
Circuit G5 provides power for the ABS warning
lamp at the instrument cluster. Ground for the ABS
warning lamp is provided by either the ABS control
module or by the ABS power relay when the relay is
not energized. The ABS control module illuminates
the lamp by providing ground on circuit G19.
Circuit G19 splices to connect to circuit B15
through a diode. When the ABS power relay is notenergized, it connects circuit B15 to circuit Z12. The
ground path for the warning lamp is through the di-
ode to circuit B15, through the ABS power relay to
ground on circuit Z12.
The diode between circuit G19 and B15 prevents
voltage from flowing to the ABS control module when
the ABS power relay switches to supply power on cir-
cuit B15.
DATA LINK CONNECTOR
Circuit D11 from cavity 23 of the ABS control mod-
ule receives data from the DRB scan tool through the
data link connector. The ABS control module trans-
mits data to the scan tool through the connector on
circuit D12. Circuit D12 originates at cavity 42 of the
ABS control module.
Through the data link connector, circuit Z12 pro-
vides ground for the DRB scan tool. Circuit Z12 ter-
minates at the right rear of the dash panel.
Circuit A4 from fuse 8 in the Power Distribution
Center (PDC) supplies power to fuse 16 in the PDC.
Fuse 16 powers circuit M1 which supplies battery
voltage to the scan tool through the diagnostic con-
nector.
HELPFUL INFORMATION
²Check fuses 4, 9 and 10 in the PDC
²Check fuse 13 in the fuse block
DIAGRAM INDEX
Component Page
ABS Power Relay........................8W-32-4
ABS Pump Motor/Sensor...................8W-32-5
ABS Warning Lamp.......................8W-32-4
ABS Control Module..................8W-32-3 thru 7
ABS Pump Motor Relay....................8W-32-5
Brake Pedal Travel Sensor...................8W-32-6
Data Link Connector......................8W-32-6
Fuse 1 Fuse Block........................8W-32-4
Fuse 3 Fuse Block........................8W-32-6
Fuse 3 (PDC)...........................8W-32-6
Fuse 4 (PDC)...........................8W-32-4
Fuse 8 (PDC)...........................8W-32-6
Fuse 10 (PDC)..........................8W-32-4
Fuse 12 Fuse Block.......................8W-32-4
Fuse 12 (PDC)..........................8W-32-6
Fuse 13 (PDC)..........................8W-32-4
Hydraulic Actuation Unit....................8W-32-3
Ignition Switch..........................8W-32-4
Powertrain Control Module (PCM)..............8W-32-6
Stop Lamp Switch........................8W-32-6
Wheel Speed Sensors......................8W-32-7
8W - 32 - 2 8W-32 ANTI-LOCK BRAKESÐYJ VEHICLESJ

MALFUNCTION INDICATOR (CHECK ENGINE)
LAMP
The Powertrain Control Module (PCM) provides
ground for the malfunction indicator (Check Engine)
lamp on circuit G3. Circuit G3 connects to cavity 32
of the PCM. Circuit G5 connects to the instrument
cluster and supplies battery voltage for the malfunc-
tion indicator lamp. When illuminated, the malfunc-
tion indicator lamp displays the message CHECK
ENGINE.
For information regarding diagnostic trouble code
access using the malfunction indicator lamp, refer to
Group 14, Fuel Systems.
UP-SHIFT LAMP
On vehicles equipped with a manual transmission,
the Powertrain Control Module (PCM) provides
ground for the Up-Shift lamp on circuit K54. Circuit
G5 provides battery voltage for the lamp.
ABS WARNING LAMP
Circuit G5 provides power for the ABS warning
lamp at the instrument cluster. Ground for the ABS
warning lamp is provided by either the ABS control
module or by the ABS power relay when the relay is
not energized. The ABS control module illuminates
the lamp by providing ground on circuit G19.
Circuit G19 splices to connect to circuit B15
through a diode. When the ABS power relay is not
energized, it connects circuit B15 to circuit Z12. The
ground path for the warning lamp is provided
through the diode to circuit B15, through the ABS
power relay to ground on circuit Z12.
The diode between circuit G19 and B15 prevents
voltage from flowing to the ABS control module when
the ABS power relay switches to supply power on cir-
cuit B15.
BRAKE WARNING LAMP
Circuit G5 provides battery voltage for the brake
warning lamp. Circuit G11 can provide ground for
the lamp in 3 ways. The first ground path is through
the ignition switch when the key is in the START po-
sition.
The second ground path for the brake warning
lamp on circuit G11 is through the case grounded
brake warning switch. When the switch closes it pro-
vides a ground.
The third ground path on circuit G11 is through
the case grounded park brake switch. When the
switch closes it provides ground.
HIGH BEAM INDICATOR LAMP
Circuit G34 supplies power for the high-beam indi-
cator lamp when the operator either flashes the opti-
cal horn (high beams) or selects high beam operation.
Circuit Z1 provides the ground path for the lamp.
Circuit L3 from the headlamp switch powers the
high beam circuits of the headlamps. On vehicles not
equipped with Daytime Running Lamps (DRL), cir-
cuit G34 double crimps to circuit L3 at the bulkhead
connector.
On vehicles equipped with DRL, circuit L3 splices
to the DRL module. The DRL module powers circuit
G34.
TURN SIGNAL INDICATOR LAMPS
Circuit L61 supplies battery voltage to the left turn
signal indicator lamp. The right turn signal indicator
lamp receives battery voltage from circuit L60. The
turn signal/hazard flasher switch powers circuits L60
and L61. Circuit Z1 provides ground for the lamps.
HELPFUL INFORMATION
²If the warning lamps, gauges and indicator lamps
don't operate, check fuse 4 in the PDC and fuse 9 in
the fuse block.
²If the illumination lamps don't operate, check fuse
10 in the fuse block.
DIAGRAM INDEX
Component Page
4WD Switch............................8W-40-9
ABS Control Module......................8W-40-5
Brake Warning Switch.....................8W-40-5
Combination Buzzer.....................8W-40-7, 8
Daytime Running Lamp (DRL) Module.........8W-40-4, 6
Engine Coolant Temperature Sensor...........8W-40-7, 8
Engine Oil Pressure Sensor..................8W-40-9
Fuse 3 (PDC).......................8W-40-3, 7, 8
Fuse 4 (PDC).......................8W-40-4, 7, 8
Fuse 7 (PDC)...........................8W-40-6
Fuse 8 (Fuse Block)...................8W-40-3, 7, 8
Fuse 9 (Fuse Block).......................8W-40-8
Fuse 10 (Fuse Block).................8W-40-3, 7, 10
Gauge Package......................8W-40-7, 8, 9
Headlamp Switch...................8W-40-3, 6, 7, 8
Headlamp Dimmer Switch...................8W-40-6
Ignition Switch......................8W-40-4, 5, 8
Instrument Cluster...................8W-40-3 thru 9
Panel Lamp Dimmer Switch..............8W-40-3, 7, 8
Park Brake Switch........................8W-40-5
Powertrain Control Module.................8W-40-4, 5
8W - 40 - 2 8W-40 INSTRUMENT CLUSTERÐYJ VEHICLESJ

SPLICE LOCATIONS
GENERAL INFORMATION
This section provides illustrations identifying the
general location of the splices in this vehicle. A splice
index is provided. Use the wiring diagrams in each
section for splice number identification. Refer to the
index for the proper splice number.
SPLICE LOCATIONS
Splice
NumberLocations Fig.
S101 Near PDC T/O.....................1
S102 Near T/O for Engine Wiring.............1
S103 RT Dash Panel Near T/o for Ground.......1
S104 Near T/O for MAP Sensor..............1
S105 Near T/O for MAP Sensor..............1
S106 Left Side of MAP Sensor..............1
S107 In ABS Wiring T/O Near Grommet........1
S108 In ABS Wiring T/O Near Grommet........1
S109 Above Brake Booster.................1
S110 Rear of Generator...................3
S111 2.5L RT Side of Valve Cover...............4
S111 4.0L RT Side of Valve Cover...............3
S112 Near T/O for PRNDL Switch............5
S113 Between Inj #2 and Inj #3.............3
S114 Near T/O for Throttle Body Wiring........3
S115 Above Bulkhead Connector.............1
S116 Above Bulkhead Connector.............1
S117 Near Data Link T/O..................1
S118 Near Data Link T/O..................1
S119 Near Data Link T/O..................1
S120 4.0L RT Side of Valve Cover...............3
S121 2.5L RT Side of Valve Cover...............4
S122 Near T/O for RT PK/TURN Lamp.........2
S123 Near T/O for RT Fog Lamp.............2
S124 Near T/O for LT Fog Lamp.............2
S125 Near T/O for LT PK/TURN Lamp.........2Splice
NumberLocations Fig.
S126 Near T/O for Headlamp...............2
S127 Near T/O for Headlamp...............2
S128 Near T/O for Headlamp...............2
S129 Near Horn T/O.....................2
S201 Near T/O for Dimmer Switch............7
S202 Near T/O for Dimmer Switch............7
S203 Near T/O for Dimmer Switch............7
S204 Near T/O for Dimmer Switch............7
S205 Near T/O for Wiper Switch.............7
S206 Near T/O for Wiper Switch.............7
S207 Near Panel Illumination T/O.............7
S208 Near Panel Illumination T/O.............7
S209 Near Panel Illumination T/O.............7
S210 Near Panel Illumination T/O.............7
S211 Near T/O for Ignition Switch............7
S212 Near T/O for Ignition Switch............7
S213 Near T/O for Radio..................6
S301 Near T/O for Park Brake Switch..........8
S302 Near T/O for Park Brake Switch..........8
S303 Near Grommet LT Rear Quarter Panel......8
S304 Near LT Rear Tail Lamp T/O............8
S305 RT Rear Quarter Panel Near Tail Lamp.....8
S306 Near T/O for Dome Lamp.......Not Shown
S307 In CHMSL Jumper Harness......Not Shown
S308 In CHMSL Jumper Harness......Not Shown
J8W-95 SPLICE LOCATIONSÐYJ VEHICLES 8W - 95 - 1