1995 JEEP XJ sensor

VEHICLE SPEED CONTROL SYSTEM
CONTENTS
page page
DIAGNOSIS............................. 2
GENERAL INFORMATION.................. 1SERVICE PROCEDURES................... 9
GENERAL INFORMATION
The vehicle speed control system (Fig. 1) is an
available option on all XJ (Cherokee) models. The
system is electronically controlled and vacuum oper-
ated. Following are general descriptions of the major
components in the vehicle speed control system. Re-
fer to Group 8W - Wiring Diagrams for complete cir-
cuit descriptions and diagrams.
SPEED CONTROL SERVO
The speed control servo is mounted to a bracket on
the right side inner fender shield in the engine com-
partment. The servo unit consists of a solenoid valve
body, a vacuum servo and the mounting bracket. The
PCM controls the solenoid valve body. The solenoid
valve body controls the application and release of
vacuum to the diaphragm of the vacuum servo. The
servo unit cannot be repaired and is serviced only as
a complete assembly.
SPEED CONTROL SWITCH
The speed control switch module is mounted to the
center of the steering wheel below the driver's airbag
module. The PCM monitors the state of the speed
control switches. The individual switches are labeled:
OFF/ON, RESUME/ACCEL, SET/COAST. Refer to
the owner's manual for more information on speed
control switch functions and setting procedures. The
individual switches cannot be repaired. If one switch
fails, the entire switch module must be replaced.
STOP LAMP SWITCH
Vehicles with the speed control option use a dual
function stop lamp switch. The switch is mounted in
the same location as the conventional stop lamp
switch, on the brake pedal mounting bracket under
the instrument panel. The PCM monitors the state of
the dual function stop lamp switch. Refer to Group 5
- Brakes for more information on stop lamp switch
service and adjustment procedures.
SERVO CABLE
The speed control servo cable is connected betweenthe speed control vacuum servo diaphragm and the
throttle control linkage. This cable causes the throt-
tle control linkage to open or close the throttle valve
in response to movement of the vacuum servo dia-
phragm.
POWERTRAIN CONTROL MODULE
The speed control electronic control circuitry is in-
tegrated into the Powertrain Control Module (PCM).
The PCM is located in the engine compartment on
the left side inner fender shield. The PCM speed con-
trol functions are monitored by the On-Board Diag-
nostics (OBD). All OBD-sensed systems are
monitored by the PCM. Each monitored circuit is as-
signed a Diagnostic Trouble Code (DTC). The PCM
will store a DTC in electronic memory for any failure
it detects. See Using On-Board Diagnostic System in
this group for more information. The PCM cannot be
repaired and must be replaced if faulty.
VACUUM RESERVOIR
The vacuum reservoir is mounted behind the left
end of the front bumper bar. The reservoir contains a
one-way check valve to trap engine vacuum in the
reservoir. When engine vacuum drops, as in climbing
a grade while driving, the reservoir supplies the vac-
uum needed to maintain proper speed control opera-
tion. The vacuum reservoir cannot be repaired and
must be replaced if faulty.
VEHICLE SPEED SENSOR
The Vehicle Speed Sensor (VSS) is a pulse genera-
tor mounted to an adapter near the transmission
(two-wheel drive) or transfer case (four-wheel drive)
output shaft. The sensor is driven through the
adapter by a speedometer pinion gear. The VSS pulse
signal to the speedometer/odometer is monitored by
the PCM speed control circuitry to determine vehicle
speed and to maintain speed control set speed. Refer
to the appropriate Powertrain Diagnostic Procedures
manual for testing of this component. Refer to Group
14 - Fuel System for service of this component.
JVEHICLE SPEED CONTROL SYSTEM 8H - 1

USING ON-BOARD DIAGNOSTIC SYSTEM
The Powertrain Control Module (PCM) monitors
critical input and output circuits of the speed control
system, making sure they are operational. A Diagnos-
tic Trouble Code (DTC) is assigned to each input and
output circuit monitored by the OBD system. Some
circuits are checked continuously and some are
checked only under certain conditions.
If the OBD system senses that a monitored circuit
is bad, it will put a DTC into electronic memory. The
DTC will stay in electronic memory as long as the
circuit continues to be bad. The PCM is programmed
to clear the memory after 50 engine starts, if the
problem does not occur again.
DIAGNOSTIC TROUBLE CODES
Diagnostic Trouble Codes (DTC) are two-digit num-
bers flashed on the malfunction indicator (Check En-
gine) lamp that identify which circuit is bad. A DTC
description can also be read using the DRB scan tool.
Refer to Group 14 - Fuel Systems for more informa-
tion.
A DTC does not identify which component in a cir-
cuit is bad. Thus, a DTC should be treated as a
symptom, not as the cause for the problem. In some
cases, because of the design of the diagnostic test
procedure, a DTC can be the reason for another DTC
to be set. Therefore, it is important that the test pro-
cedures be followed in sequence, to understand what
caused a DTC to be set.
See Speed Control Diagnostic Trouble Code chart
for DTC's which apply to the speed control system.Refer to the Powertrain Diagnostic Procedures man-
ual to diagnose an on-board diagnostic system trou-
ble code.
RETRIEVING DIAGNOSTIC TROUBLE CODES
To start this function, cycle the ignition switch ON-
OFF-ON-OFF-ON within 5 seconds. This will cause
any DTC stored in the PCM memory to be displayed.
The malfunction indicator (Check Engine) lamp will
display a DTC by flashing on and off. There is a
short pause between flashes and a longer pause be-
tween digits. All DTC's displayed are two-digit num-
bers, with a four-second pause between codes.
An example of a DTC is as follows:
(1) Lamp on for 2 seconds, then turns off.
(2) Lamp flashes 1 time pauses and then flashes 5
times.
(3) Lamp pauses for 4 seconds, flashes 3 times,
pauses, then flashes 4 times.
The two DTC's are 15 and 34. Any number of
DTC's can be displayed, as long as they are in mem-
ory. The lamp will flash until all stored DTC's are
displayed (55 = end of test).
If a DTC 15 is observed, see diagnosis for Vehicle
Speed Sensor in this group. If a DTC 34 is observed,
see diagnosis for Speed Control Servo and Power-
train Control Module in this group. Correct any prob-
lems found in your diagnosis, then recheck for DTC
after corrections are completed.
VEHICLE SPEED SENSOR
For diagnosis of the VSS, refer to the appropriate
Powertrain Diagnostic Procedures manual.
SPEED CONTROL DIAGNOSTIC TROUBLE CODE
JVEHICLE SPEED CONTROL SYSTEM 8H - 5

The two pivot cranks are joined by a connecting link,
and a drive link connects the motor crank to the drive
link near the left pivot. Pressed-in plastic bushings in
the ends of the links can be replaced if worn or dam-
aged.
WINDSHIELD WIPER MOTOR
The two-speed permanent magnet wiper motor has
an integral transmission and park switch. The motor
is mounted to the engine side of the cowl panel with
a reinforcement/stud plate and a rubber-isolated
mounting bracket. The wiper motor output shaft
passes through the cowl panel into the cowl plenum
area, where a crank arm attached to the output shaft
drives the wiper drive link.
Wiper speed is controlled by current flow to the ap-
propriate set of brushes. The wiper motor completes
its wipe cycle when the switch is turned OFF, and
parks the blades in the lowest portion of the wipe
pattern. The wiper motor assembly can not be re-
paired. If faulty, the entire motor assembly must be
replaced. The crank arm, mounting bracket, and re-
inforcement/stud plate are available for service.
LIFTGATE WIPER MOTOR
The liftgate wiper motor contains integral elec-
tronic controls and a transmission to provide three
operating modes:
²intermittent wipe with a fixed 5 to 8 second delay
between wipes
²constant wipe that operates when the liftgate
washer is operated
²a park mode that runs the motor until the wiper
blade reaches the park position after the liftgate
wiper switch or ignition switch is turned OFF.
The liftgate wiper motor can not be repaired. If
faulty, the entire assembly must be replaced.
WINDSHIELD WIPER/WASHER SWITCH
Controls for the windshield wiper and washer sys-
tems are contained in the multi-function switch con-
trol lever. The multi-function switch is mounted on
the left side of the steering column between the
steering wheel and the instrument panel. This switch
also controls many other functions. The multi-func-
tion switch can not be repaired. If any function of the
switch is faulty, the entire switch must be replaced.
LIFTGATE WIPER/WASHER SWITCH
The single two-function switch on the instrument
panel right of the steering column controls the lift-
gate wiper and washer functions. The rocker-type
switch features a detent in the WIPE position, but
only momentary contact in the WASH position. Both
the liftgate wiper and liftgate washer motors will op-
erate continuously for as long as the switch is held in
the WASH position. The switch can not be repaired;
if faulty, it must be replaced.
INTERMITTENT WIPE MODULE
In addition to low and high speed, the optional inter-
mittent wipe system has a delay mode. The delay mode
has a range of 2 to 15 seconds. The length of the delay
is selected with a variable resistor in the wiper (multi-
function) switch and is accomplished by electronic cir-
cuitry within the intermittent wipe module. If the
washer knob is depressed while the wiper (multi-func-
tion) switch is in the OFF position, the intermittent
wipe module will operate the wiper motor for approxi-
mately 2 wipes and automatically turn the motor off.
The intermittent wipe module is mounted to the
lower instrument panel, behind the knee blocker and
near the steering column with a hook and loop fas-
tener patch. The module can not be repaired.
WINDSHIELD WASHER NOZZLES
The two fluidic washer nozzles are riveted into
openings in the cowl grille panel below the wind-
shield and are not adjustable. Washer fluid is fed to
the nozzles through hoses clipped to the underside of
the cowl grille panel. The nozzles can not be repaired
and, if faulty, should be replaced.
LIFTGATE WASHER NOZZLE
The single liftgate washer nozzle snaps into place
on the liftgate wiper arm. Washer fluid is fed to the
nozzle from the washer reservoir in the engine com-
partment. A liftgate washer hose system is routed
through the body of the vehicle with the body wiring
harness from the reservoir to the liftgate. The fluid
passes through a nipple on the liftgate wiper motor
output shaft bezel to a hose clipped to the underside
of the wiper arm. The nozzle can not be repaired and,
if faulty, should be replaced.
WASHER RESERVOIR
The washer solvent reservoir is mounted to the left
front inner fender shield near the cowl panel. The
same reservoir is used for both the standard front
and optional liftgate washer systems. It also has a
provision for a low washer fluid level sensor. Refer to
Group 8E - Instrument Panel and Gauges for diagno-
sis and service of the sensor. The reservoir and filler
cap are available for service.
WASHER PUMPS
The washer pump and motor are press-fit into a
rubber grommet near the bottom of the washer res-
ervoir. Vehicles with the optional liftgate wiper/
washer system have two pumps installed in the
single reservoir. A permanently lubricated and sealed
motor is coupled to a rotor-type pump. Washer fluid
is gravity fed from the reservoir to the pump. The
pump then pressurizes the fluid and forces it through
the plumbing to the nozzles when the motor is ener-
gized. The pump and motor can not be repaired. If
faulty, the entire assembly must be replaced.
8K - 2 WIPER AND WASHER SYSTEMS - XJJ

(2) Reservoir filler neck is held in reservoir by a
grommet. Remove reservoir filler neck (Fig. 17) by
pulling sharply away from reservoir.
(3) Remove 2 reservoir mounting screws.
(4) Raise vehicle on hoist and remove left front in-
ner wheelhouse splash shield.
(5) Disconnect hose(s) from washer pump(s) and
drain solvent from reservoir into a clean container
for re-use.
(6) Disconnect wiring from pump(s) and fluid level
sensor (if equipped).
(7) Remove washer pumps from reservoir by pull-
ing out of grommets.
(8) To remove reservoir, slide slightly towards rear
of vehicle to release hook (Fig. 17) from inner fender
slot. Then lower front of reservoir and slide unit for-
ward to remove.(9) Reverse removal procedures to install. Use new
grommets when installing washer pumps.
Fig. 16 Washer Pumps (LHD)
Fig. 17 Washer Reservoir and Pumps (RHD)
JWIPER AND WASHER SYSTEMS - XJ 8K - 9

DAYTIME RUNNING LIGHTS (CANADA ONLY)ÐXJ
SERVICE INFORMATION
The Daytime Running Lights (Headlamps) System
is installed on vehicles manufactured for sale in Can-
ada only. The headlamps are illuminated when the
ignition switch is turned to the ON position. The
DRL module receives a vehicle-moving signal from
the vehicle speed sensor. This provides a constant
headlamps-oncondition as long as the vehicle is
moving. The lamps are illuminated at less than 50
percent of normal intensity.
DRL MODULE REPLACEMENTÐXJ
REMOVAL
The Daytime Running Lights (DRL) module is lo-
cated on the right fender inner panel adjacent to the
dash panel (Fig. 24).
(1) Disconnect the wire harness connector from the
module.
(2) Remove the screws that attach the module to
the fender inner panel.
(3) Remove the module from the fender inner
panel.
INSTALLATION
(1) Position the module on the right fender inner
panel.
(2) Install the attaching screws. Tighten the
screws securely.(3) Connect the wire harness connector to the mod-
ule.
Fig. 24 Daytime Running Lights (DRL) Module
JLAMPSÐXJ VEHICLES 8L - 15

(3) Insert a replacement bulb in the lamp base
socket and rotate it clockwise.
(4) Connect the wire harness connector to the
lamp.
DAYTIME RUNNING LIGHTS (CANADA ONLY)ÐYJ
The Daytime Running Lights (Headlamps) System
is installed on vehicles manufactured for sale in Can-
ada only. The headlamps are illuminated when the
ignition switch is turned to the ON position. The
DRL module receives a vehicle-moving signal from
the vehicle speed sensor. This provides a constant
headlamps-oncondition as long as the vehicle is
moving. The lamps are illuminated at less than 50
percent of normal intensity.
DRL MODULE REPLACEMENTÐYJ
REMOVAL
The daytime running light module is located on the
left fender inner panel below the engine air cleaner
housing.
(1) Remove the engine air cleaner housing for ac-
cess to the DRL module.
(2) Disconnect the wire harness connector from the
module.
(3) Remove the screws that attach the module to
the fender inner panel (Fig. 21).(4) Remove the module from the fender inner
panel.
INSTALLATION
(1) Position the DRL module on the left, fender in-
ner panel.
(2) Install the attaching screws. Tighten the
screws securely.
(3) Connect the wire harness connector to the mod-
ule.
(4) Install the air cleaner housing.
Fig. 21 Daytime Running Lamp Module
8L - 30 LAMPSÐYJ VEHICLESJ

RESTRAINT SYSTEMS
CONTENTS
page page
AIRBAG SYSTEM......................... 1
DIAGNOSIS............................. 2GENERAL INFORMATION.................. 1
SERVICE PROCEDURES................... 2
AIRBAG SYSTEM
WARNING: THIS AIRBAG SYSTEM IS A SENSITIVE,
COMPLEX MECHANICAL UNIT. BEFORE ATTEMPT-
ING TO REMOVE OR INSTALL THE AIRBAG SYS-
TEM OR RELATED STEERING WHEEL AND
STEERING COLUMN COMPONENTS YOU MUST
FIRST DISARM THE AIRBAG FIRING MECHANISM.
FAILURE TO DO SO COULD RESULT IN ACCIDEN-
TAL DEPLOYMENT AND POSSIBLE PERSONAL IN-
JURY.
WARNING: THE AIRBAG MODULE INFLATOR/SEN-
SOR ASSEMBLY CONTAINS SODIUM AZIDE AND
POTASSIUM NITRATE. THESE MATERIALS ARE
POISONOUS AND EXTREMELY FLAMMABLE. CON-
TACT WITH ACID, WATER OR HEAVY METALS MAY
PRODUCE HARMFUL AND IRRITATING GASES (SO-
DIUM HYDROXIDE IS FORMED IN THE PRESENCE
OF MOISTURE) OR COMBUSTIBLE COMPOUNDS.
DO NOT ATTEMPT TO DISMANTLE THE MODULE
OR TAMPER WITH ITS ARMING LEVER. DO NOT
PUNCTURE, INCINERATE, OR BRING INTO CON-
TACT WITH ELECTRICITY. DO NOT STORE AT TEM-
PERATURES EXCEEDING 200ÉF.WARNING: REPLACE AIRBAG SYSTEM COMPO-
NENTS WITH PARTS SPECIFIED IN THE CHRYSLER
MOPAR PARTS CATALOG ONLY. IT IS OF PARTICU-
LAR IMPORTANCE THAT ANY COMPONENTS USED
IN THIS MECHANICALLY-FIRED AIRBAG SYSTEM
NOT BE MIXED WITH COMPONENTS FROM AN
ELECTRICALLY-FIRED AIRBAG SYSTEM. SUBSTI-
TUTE PARTS MAY APPEAR THE SAME, BUT INTER-
NAL DIFFERENCES MAY RESULT IN INFERIOR
OCCUPANT PROTECTION.
WARNING: THE FASTENERS, SCREWS, AND
BOLTS, ORIGINALLY USED FOR THE AIRBAG COM-
PONENTS, HAVE SPECIAL COATINGS AND ARE
SPECIFICALLY DESIGNED FOR THE AIRBAG SYS-
TEM. THEY MUST NEVER BE REPLACED WITH ANY
SUBSTITUTES. ANYTIME A NEW FASTENER IS
NEEDED, REPLACE WITH THE CORRECT FASTEN-
ERS PROVIDED IN THE SERVICE PACKAGE OR
SPECIFIED IN THE CHRYSLER MOPAR PARTS CAT-
ALOG.
GENERAL INFORMATION
The airbag system is a standard equipment safety
device on XJ (Cherokee) models. It is designed to pro-
tect the driver from serious injury, caused by a fron-
tal impact of the vehicle. If the airbag module
assembly is defective and non-deployed, refer to
Chrysler Corporation current return list for proper
handling procedures.
Following are general descriptions of the major
components in the airbag system.AIRBAG MODULE
The airbag module protective cover is the only vis-
ible part of the system. The module is mounted di-
rectly to the steering wheel. Under the airbag
module cover, the airbag cushion and its supporting
components are contained. The airbag module con-
tains a housing to which the cushion and impact sen-
sor/inflator assembly are attached and sealed. The
airbag module is non-serviceable, and must be re-
placed if deployed or damaged in any way.
The impact sensor/inflator assembly is mounted to
the back of the module. The inflator seals the hole in
JRESTRAINT SYSTEMS 8M - 1

the airbag cushion so it can discharge the gas it pro-
duces directly into the cushion. The protective cover
is fitted to the front of the airbag module and forms
a decorative cover in the center of the steering wheel.
Upon airbag deployment, this cover will split hori-
zontally.
STORAGE
The airbag module must be stored in its original,
special container until used for service. Also, it must
be stored in a clean, dry environment; away from
sources of extreme heat, sparks, and high electrical
energy. Always place or store the module on a surface
with the trim cover facing up to minimize movement
in case of accidental deployment.
IMPACT SENSOR/INFLATOR ASSEMBLY
The impact sensor/inflator assembly is mounted to
the back of the airbag module. It seals the hole in
the steering wheel side of the airbag cushion so that
gas produced in the inflator can be discharged di-
rectly into the cushion.
The impact sensor provides verification of the di-
rection and severity of the impact. A spherical sens-
ing mass housed in a cylinder will move forward and
rotate a D-shaft when the vehicle is subjected to a
frontal impact of sufficient severity. Airbag inflation
is designed to occur at a precisely calibrated vehicle
deceleration force, and is not linked to vehicle road
speed.The D-shaft retains two spring-loaded firing pins.
When a firing pin is released by the D-shaft, it
strikes and ignites a primer. The primer then reacts
with the pelletized, solid generant contained in the
inflator to produce the nitrogen gas that inflates the
airbag cushion.
ARMING/DISARMING MECHANISM
The steering wheel hub incorporates an airbag
arming/disarming mechanism and a specially de-
signed nut-blocker. The nut-blocker serves as a safety
to prevent removal of the airbag module until the
unit has been disarmed. A removable plastic cover
plug on the top, outer hub of the steering wheel al-
lows access to the arming screw.
When the airbag module is disarmed, the arming
screw extends upward from the steering wheel hub.
This will prevent installation of the plastic cover
plug. Also, the nut-blocker is retracted to allow ac-
cess to the two upper airbag module mounting nuts.
When the airbag module is armed, the plastic cover
plug will install flush with the outer surface of the
steering wheel hub. In addition, the nut-blocker will
prevent access to the two upper airbag module
mounting nuts.
DIAGNOSIS
This mechanical airbag system can not be diag-
nosed or repaired. The only serviced component is
the airbag module assembly. If the airbag module isdamaged in any way or deployed, it must be re-
placed.
SERVICE PROCEDURES
AIRBAG SYSTEM SERVICE (DEPLOYED)
Any vehicle which is to be returned to use after an
airbag deployment, must have the airbag module re-
placed. This is a one-time component and cannot be
reused.
AIRBAG MODULE HANDLING
UNDEPLOYED
At no time should any source of electricity be per-
mitted near the inflator on the back of the module.
When carrying an undeployed module, the trim cover
should be pointed away from the body to minimizeinjury in the event of accidental deployment. If the
module is placed on a bench or other surface, the
plastic trim cover should be face up to minimize
movement in case of accidental deployment.
In addition, the airbag module should be disarmed
whenever the steering wheel or steering column re-
quires service or removal. Failure to observe this
warning could result in accidental airbag deployment
and possible personal injury. Refer to Group 19 -
Steering for more service procedures on steering
wheel and steering column.
8M - 2 RESTRAINT SYSTEMSJ