CHRYSLER VOYAGER 1996 Service Manual

FRONT DOOR SPEAKER
REMOVAL
(1) Remove front door trim panel as necessary to
gain access to door speaker. Refer to Group 23, Body
for proper procedures.
(2) Remove screws holding speaker to bracket (Fig.
16).
(3) Remove speaker from bracket.
(4) Disconnect wire connector from speaker.
(5) Remove speaker.
INSTALLATION
For installation, reverse the above procedure.
REMOTE RADIO SWITCHES
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO GROUP 8M - PASSIVE
RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
REMOVAL
(1) Disconnect and isolate the battery negative
cable. Wait two minutes for the airbag system capac-
itor to discharge before further service.
(2) From the underside of the steering wheel,
remove the (3) bolts that secure the driver side air-
bag module to the steering wheel.
(3) Pull the airbag module away from the steering
wheel far enough to access the wire harness connec-
tors on the back of the airbag module.
(4) Unplug the airbag module and horn switch
wire harness connectors from the back of the airbag
module.
(5) Remove the driver side airbag module from the
vehicle.
(6) Remove the steering wheel from the steering
column. Refer to Group 19±Steering, for service pro-
cedure.
(7) Unplug the wire harness connector from the
remote radio switch (s).
(8) Remove three screws securing steering wheel
rear cover. Refer to Group 19, Steering for serivce
procedure.
(9) Remove the remote radio switch from the steer-
ing wheel by depressing tabs on each side of switch..
NOTE: The right remote radio switch back is white
in color. The left switch back is black in color. The
right/left remote radio switch orientation is with the
steering wheel installed, and driver in drivers seat.
INSTALLATION
For installation, reverse the above procedure. The
switches can only be installed one way. Be careful to
index them correctly before pressing them into place.
Tighten the airbag module mounting screws to 10.2
N´m (90 in. lbs.).
Fig. 15 Right Instrument Panel Speaker
Fig. 16 Front Door Speaker
NSAUDIO SYSTEMS 8F - 9
REMOVAL AND INSTALLATION (Continued)

QUARTER PANEL SPEAKER
REMOVAL
(1) Remove quarter trim bolster from quarter trim
panel.
(2) Remove screws holding speaker to inner quar-
ter panel (Fig. 17).
(3) Separate speaker from quarter panel.
(4) Disconnect wire connector from speaker.
(5) Remove speaker.
INSTALLATION
For installation, reverse the above procedure.
D±PILLAR SPEAKER
REMOVAL
(1) Remove D-pillar trim panel as necessary to
gain access to door speaker. Refer to Group 23, Body
for proper procedures.
(2) Disconnect wire connector from speaker.
(3) Remove by sliding speaker out of bracket by
pushing on magnet. The capacitor is wrapped with
foam tape (Fig. 18).
(4) Remove speaker.
INSTALLATION
For installation, reverse the above procedure.
Fig. 17 Quarter Panel Speaker
Fig. 18 D±Pillar Speaker
8F - 10 AUDIO SYSTEMSNS
REMOVAL AND INSTALLATION (Continued)

HORNS
CONTENTS
page page
DESCRIPTION AND OPERATION
INTRODUCTION......................... 1
DIAGNOSIS AND TESTING
HORN RELAY........................... 1
HORN SYSTEM.......................... 3
HORN SYSTEM TEST..................... 3HORN................................. 1
HORNS SOUND CONTINUOUSLY............ 3
HORNS WILL NOT SOUND................ 2
REMOVAL AND INSTALLATION
HORN SWITCH.......................... 4
HORNS................................ 4
DESCRIPTION AND OPERATION
INTRODUCTION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAG, SEE GROUP 8M, RESTRAINT SYSTEMS FOR
SAFETY PRECAUTIONS. DISCONNECT THE NEGA-
TIVE CABLE FROM THE BATTERY BEFORE SER-
VICING COMPONENTS INVOLVING THE AIRBAG
SYSTEM. ACCIDENTAL DEPLOYMENT OF AIRBAG
AND PERSONAL INJURY CAN RESULT.
The horn circuit consists of a horn switch, clock-
spring, horn relay, horns and Body Control Module
(Fig. 1). The horn switch is a membrane switch
located in the airbag cover. The horns are located for-
ward of the left front wheel behind the bumper fas-
cia. The horn relay plugs into the junction block. For
circuit information and component locations refer to
Group 8W, Wiring Diagrams.
DIAGNOSIS AND TESTING
HORN
(1) Disconnect wire connector at horn.
(2) Using a voltmeter, connect one lead to ground
terminal and the other lead to the positive wire ter-
minal (Fig. 3).
(3) Depress the horn switch, battery voltage
should be present.
(4) If no voltage, refer to Horn Will Not Sound. If
voltage is OK, go to step Step 5.
(5) Using ohmmeter, test ground wire for continu-
ity to ground.
(6) If no ground repair as necessary.
(7) If wires test OK and horn does not sound,
replace horn.
HORN RELAY
(1) Remove horn relay.
(2) Using ohmmeter, test between relay connector
terminals 85 to 86 for 70 to 75 ohms resistance (Fig.
2). If resistance not OK, replace relay.
(3) Test for continuity between ground and termi-
nal 85 of horn relay.
(a) When the horn switch is not depressed, no
continuity should be present.
(b) Continuity to ground when horn switch is
depressed.
(c) If continuity is not correct repair horn
switch or wiring as necessary, refer to Group 8W,
Wiring Diagrams Group 8M Restraint System for
Driver's Airbag Module removal procedures.
(4) Using voltmeter, test voltage at:
(a) Terminals 30 and 86 of the horn relay to
body ground.
(b) If NO voltage check fuse 7 of the BCM.
(c) If incorrect voltage repair as necessary. Refer
to Group 8W, Wiring Diagrams.
(5) Insert a jumper wire between terminal 30 and
87 of the power distribution center.
(a) If horn sounds replace relay.
Fig. 1 Horn System
NSHORNS 8G - 1

(b) If the horn does not sound, install horn relay
and refer to Horn Test.
HORNS WILL NOT SOUND
Check horn fuse 6 in the Power Distribution Cen-
ter and fuse 7 in the Junction Block. If fuse is blown
refer to FUSE BLOWN section. If fuse is OK, refer to
FUSE OK section.
FUSE BLOWN
(1) Verify condition of battery terminals and volt-
age, refer to Group 8A, Battery. If battery connec-
tions and battery charge is OK proceed to Step 2.
(2) Using a voltmeter, test for battery voltage at
both sides of horn fuse 7. If voltage is OK, on both
sides of fuse, proceed to Fuse OK. If voltage is OK,
on one side of fuse, the fuse is blown, proceed to Step
3.
(3) Using a suitable ammeter in place of the fuse,
test amperage draw of the horn circuit. If amperage
draw is greater than 20 amps without the horn
switch depressed, a grounded circuit exists between
the fuse and the horn relay. Proceed to Step 4. If
amperage draw is greater than 20 amps with the
horn switch depressed, a grounded circuit exists
between the horn relay and the horn. Proceed to step
Step 5.
(4) Remove the horn relay from the Junction
Block. If the amperage draw drops to 0 amps, the
horn switch or circuit is shorted. Refer to group 8W,
Wiring Diagrams for circuit information. If the
amperage draw does not drop to 0 amps, repair short
at the Junction Block.
(5) Disengage a wire connector from one of the
horns. If amperage drops and the connected horn
sounds, replace the faulty horn. If amperage does not
drop with both horns disconnected and the horn
switch depressed, proceed to Step 6.
(6) Using a continuity tester, with the horns dis-
connected test continuity of the X2 cavity of the horn
relay to ground. Refer to Group 8W, Wiring Diagrams
for circuit information. If continuity is detected, the
circuit is grounded between the Junction Block and
the horns. Locate and repair pinched harness.
FUSE OK
(1) Remove the horn relay from the Junction
Block.
(2) Using a continuity tester, Depress horn switch
and test continuity from the X3 cavity of the horn
relay to ground. Refer to Group 8W, Wiring Diagrams
for circuit information.
(a) If continuity is detected, proceed to Step 3.
(b) If NO continuity, proceed to Step 4.
(3) Using a suitable jumper wire, jump across the
fuse F62 cavity and the X2 cavity of the horn relay in
the Junction Block.
(a) If the horn sounds, replace the horn relay.
(b) If the horn does not sound, proceed to Step 4.
(4) Remove airbag/horn pad from steering wheel.
Refer to Group 8M, Restraint Systems for proper pro-
cedures.
(5) Test continuity across horn switch connectors
with horn switch depressed.
(a) If continuity is detected, repair open circuit
between the relay and the horn switch.
(b) If NO continuity, replace airbag cover.
(6) Install horn relay into Junction Block.
(7) Disengage wire connectors from horns.
(8) Using a voltmeter, with the horn switch
depressed test voltage across horn connector termi-
nals of the wire harness (Fig. 3).
(a) If voltage is detected, replace horns.
(b) If NO voltage, proceed to step Step 9.
(9) With the horn switch depressed, test for volt-
age between the X2 circuit and ground.
(a) If voltage OK, repair system ground at right
cowl area. Refer to Group 8W, Wiring Diagrams.
(b) If NO voltage, repair open X2 circuit between
the relay and the horns.
Fig. 2 Horn Relay
Fig. 3 Horn and Connector
8G - 2 HORNSNS
DIAGNOSIS AND TESTING (Continued)

HORNS SOUND CONTINUOUSLY
CAUTION: Continuous sounding of horns may
cause relay to fail.
The horn switch (membrane) sometimes can be the
cause without the switch being depressing.
(1) Remove the horn relay from the junction block.
(2) Using a continuity tester, test continuity from
the X3 cavity of the horn relay to ground. Refer to
Group 8W, Wiring Diagrams for circuit information.
(a) If continuity is detected, proceed to step Step
3.
(b) If NO continuity, replace the horn relay.
(3) Remove the airbag/horn pad from the steering
wheel and disengage horn connector.
(4) Install horn relay into junction block.
(a) If horn does not sound, replace airbag cover/
horn pad.
(b) If horn sounds, repair grounded X3 circuit
from junction block to clockspring in steering in
steering column. Refer to Group 8W, Wiring Dia-
grams.
HORN SYSTEM
Refer to Horn System Test below. If the horn does
not sound, check horn fuse located in the Power Dis-
tribution Center. If the fuse is blown, replace with
the correct fuse. If the horn fail to sound and the
new fuse blows when depressing the horn switch, a
short circuit in the horn or the horn wiring between
the fuse terminal and the horn is responsible, or a
defective horn switch allowed the horn to burn out is
responsible.
If the fuse is OK, test horn relay refer to Horn
Relay Test.
If the relay is OK, test horn. Refer to Horn System
Test.
CAUTION: Continuous sounding of horn may
cause horn relay to fail.
Should the horn sound continuously:
²Unplug the horn relay from Power Distribution
Center.
²Refer to Horn Relay Test.
Refer to Group 8W, Wiring Diagrams for circuit
and wiring information.
HORN SYSTEM TEST
CONDITION POSSIBLE CAUSE CORRECTION
Horn sounds continuously.
NOTE: Immediately unplug horn
relay in the Power Distribution
Center (PDC)(1) Faulty horn relay.
(2) Horn control circuit to relay
shorted to ground.
(3) Pinched horn switch wire under
Driver Airbag Module.
(4) Defective horn switch(1) Refer to horn relay test.
(2) Check terminal 85 in Junction
Block for continuity to ground. If
continuity to ground indicates:
(a) Steering Wheel horn switch/lead
shorted to ground.
(b) Wiring harness shorted to
ground. Find the short and repair as
necessary.
(3) Replace Driver Airbag Module.
(4) Replace Driver Airbag Module.
Horn sound intermittently as the
steering wheel is turned.(1) Horn relay control circuit X3 is
shorted to ground inside steering
column or wheel.
(2) Pinched horn switch wire under
Driver Airbag Module
(3) Defective horn switch(1) Remove Driver Airbag Module
and/or wheel. Check for rubbing or
loose wire/connector, repair as
necessary.
(2) Replace Driver Airbag Module.
(3) Replace Driver Airbag Module.
Horn does not sound (1) Check fuse 6 in PDC
(2) No Voltage at horn relay
terminals 30 & 86, and fuse is OK.
(3) Open circuit from terminal 85 of
the horn relay to horn switch, X3
circuit.
(4) Defective or damaged horn.
(5) Defective horn switch(1) Replace fuse if blown repair as
necessary.
(2) No voltage, repair the A6 circuit
as necessary.
(3) Repair circuit as necessary.
(4) Voltage at horn when horn switch
is pressed, replace horn.
(5) Replace Driver Airbag Module.
NSHORNS 8G - 3
DIAGNOSIS AND TESTING (Continued)

CONDITION POSSIBLE CAUSE CORRECTION
Fuse blows when horn sounds (1) Short circuit in horn or horn
wiring(1) Remove horn relay, check for
shorted horn or horn wiring.
Disconnect horn wire harness to
isolate short and repair as
necessary.
Fuse blows without blowing horn (1) Short circuit (1) Remove relay, install new fuse, if
fuse does not blow replace horn
relay. If fuse blows with relay
removed, check for short to ground
with ohmmeter on circuit between
terminals 30 & 86 and the fuse
terminal. Repair as necessary.
NOTE: For wiring repairs refer to
Group 8W, Wire Diagrams.
REMOVAL AND INSTALLATION
HORN SWITCH
The horn switch is molded into the airbag cover.
The horn switch cannot be serviced separately. Refer
to Group 8M, Restraint System for Driver Airbag
Module Removal and Installation procedures.
HORNS
REMOVAL
(1) Hoist and support the front of the vehicle on
safety stands.
(2) From behind the front fascia and forward of
the left front wheel, disconnect the wire connectors
from horn.
(3) Remove the mount bracket attaching nut from
the bottom of radiator closure panel. Do not remove
the horn from mounting bracket (Fig. 4).
(4) Separate the horn from vehicle.
INSTALLATION
For installation reverse the above procedures.
Fig. 4 Horn Removal/Installation
8G - 4 HORNSNS
DIAGNOSIS AND TESTING (Continued)

VEHICLE SPEED CONTROL SYSTEM
CONTENTS
page page
GENERAL INFORMATION
INTRODUCTION......................... 1
DESCRIPTION AND OPERATION
AUTOMATIC SPEED CONTROL OVERSPEED
REDUCTION........................... 2
POWERTRAIN CONTROL MODULE.......... 2
SERVO CABLE.......................... 2
SPEED CONTROL SERVO.................. 1
SPEED CONTROL SWITCHES.............. 1
STOP LAMP SWITCH..................... 2
VACUUM RESERVOIR.................... 3
VEHICLE SPEED AND DISTANCE............ 3
DIAGNOSIS AND TESTING
CHECKING FOR DIAGNOSTIC CODES........ 3
ELECTRICAL TESTS AT POWERTRAIN
CONTROL MODULE..................... 6OVERSHOOT/UNDERSHOOT FOLLOWING
SPEED CONTROL SET................... 3
ROAD TEST............................ 3
SERVO VACUUM TEST.................... 6
SPEED CONTROL ELECTRICAL TEST........ 4
SPEED CONTROL SWITCH TEST............ 6
STOP LAMP SWITCH TEST................ 6
VACUUM SUPPLY TEST................... 8
VEHICLE SPEED SENSOR................. 8
REMOVAL AND INSTALLATION
POWERTRAIN CONTROL MODULE.......... 9
SPEED CONTROL CABLE.................. 9
SPEED CONTROL SERVO.................. 8
SPEED CONTROL SWITCHES.............. 9
STOP LAMP SWITCH.................... 9
VACUUM RESEROIR..................... 10
VEHICLE SPEED SENSOR................ 10
GENERAL INFORMATION
INTRODUCTION
The speed control system is electronically con-
trolled and vacuum operated. The electronic control
is integrated into the powertrain control module,
located next to battery. The controls are located on
the steering wheel and consist of the ON/OFF, SET,
RESUME/ACCEL, CANCEL and DECEL buttons
(Fig. 1).
DESCRIPTION AND OPERATION
SPEED CONTROL SERVO
The servo unit consists of a solenoid valve body,
and a vacuum chamber. The PCM controls the sole-
noid 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 SWITCHES
There are two separate switch pods that operate
the speed control system. The steering-wheel-
mounted switches use multiplexed circuits to provide
inputs to the PCM for ON, OFF, RESUME, ACCEL-
ERATE, SET, DECEL and CANCEL modes. Refer to
the owner's manual for more information on speed
control switch functions and setting procedures.
When speed control is selected by depressing the
ON switch, the PCM allows a set speed to be stored
in RAM for speed control. To store a set speed,
depress the SET switch while the vehicle is moving
at a speed between 30 and 85 mph. In order for the
speed control to engage, the brakes cannot be
applied, nor can the gear selector be indicating the
transmission is in Park or Neutral.
The speed control can be disengaged manually by:
²Stepping on the brake pedal
Fig. 1 Speed Control Switches
NSVEHICLE SPEED CONTROL SYSTEM 8H - 1

²Depressing the OFF switch
²Depressing the CANCEL switch.
NOTE: Depressing the OFF switch or turning off
the ignition switch will erase the set speed stored
in the PCM.
For added safety,the speed control system is pro-
grammed to disengaged for any of the following con-
ditions:
²An indication of Park or Neutral
²An rpm increase without a VSS signal increase
(indicates that the clutch has been disengaged)
²Excessive engine rpm (indicates that the trans-
mission may be in a low gear)
²The VSS signal increases at a rate of 10 mph
per second (indicates that the co-efficient of friction
between the road surface and tires is extremely low)
²The VSS signal decreases at a rate of 10 mph
per second (indicates that the vehicle may have
decelerated at an extremely high rate)
²If the actual speed is not within 20 mph of the
set speed
The previous disengagement conditions are pro-
grammed for added safety.
Once the speed control has been disengaged,
depressing the ACCEL switch when speed is greater
than 25 mph restores the vehicle to the target speed
that was stored in the PCM.
NOTE: Depressing the OFF switch will erase the
set speed stored in the PCM's RAM.
While the speed control is engaged, the driver can
increase the vehicle speed by depressing the ACCEL
switch. The new target speed is stored in the PCM
when the ACCEL is released. The PCM also has a
9tap-up9feature in which vehicle speed increases at a
rate of approximately 2 mph for each momentary
switch activation of the ACCEL switch. The PCM
also provides a means to decelerate without disen-
gaging speed control. To decelerate from an existing
recorded target speed, depress and hold the COAST
switch until the desired speed is reached, then
release the switch.
The individual switches cannot be repaired. If one
switch fails, the entire switch module must be
replaced.
AUTOMATIC SPEED CONTROL OVERSPEED
REDUCTION
Transmission control software includes an auto-
matic speed control overspeed reduction feature. This
maintains vehicle speed at the selected set point
when descending a grade.
The Transmission Control Module (TCM) first
senses that the speed control is set. If the set speedis exceeded by more than 4 mph (6.5 km/hr) and the
throttle is closed, the TCM causes the transaxle to
downshift to THIRD gear. After downshifting, the
automatic speed control resumes normal operation.
To ensure that an upshift is appropriate after the set
speed is reached, the TCM waits until the speed con-
trol system opens the throttle at least 8 degrees
before upshifting to OVERDRIVE again.
If the driver applies the brakes, canceling auto-
matic speed control operation with the transaxle still
in THIRD gear, the TCM maintains this gear until
the driver opens the throttle at least 8 degrees to
avoid an inappropriate upshift. The upshift is also
delayed for 0.5 seconds after reaching the 8 degrees
throttle opening in anticipation that the driver might
open the throttle enough to require THIRD gear.
This will avoid unnecessary and disturbing transmis-
sion cycling. If the automatic speed control RESUME
feature is used after braking, the upshift is delayed
until the set speed is achieved to reduce cycling and
provide better response.
STOP LAMP SWITCH
Vehicles equipped with the speed control option use
a dual function stop lamp switch. The switch is
mounted 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 ser-
vice and adjustment procedures.
SERVO CABLE
The speed control servo cable is connected between
the speed control vacuum servo diaphragm and the
throttle body control linkage. This cable causes the
throttle control linkage to open or close the throttle
valve in response to movement of the vacuum servo
diaphragm.
POWERTRAIN CONTROL MODULE
The speed control electronic control circuitry is
integrated into the Powertrain Control Module
(PCM). The PCM is located in the engine compart-
ment. The PCM speed control functions are moni-
tored by the On-Board Diagnostics (OBD). All OBD-
sensed systems are monitored by the PCM. Each
monitored circuit is assigned a Diagnostic Trouble
Code (DTC). The PCM will store a DTC in electronic
memory for any failure it detects. See On-Board
Diagnostic Tests in this group for more information.
The PCM cannot be repaired and must be replaced if
faulty.
USE THE DRB SCAN TOOL TO REPROGRAM
THE NEW PCM WITH THE VEHICLES ORIGI-
NAL IDENTIFICATION NUMBER (VIN) AND
THE ORGINAL VEHICLES MILAGE. IF THIS
8H - 2 VEHICLE SPEED CONTROL SYSTEMNS
DESCRIPTION AND OPERATION (Continued)

STEP IS NOT DONE A DIAGONSTIC TROUBLE
CODE (DTC) MAY BE SET.
VACUUM RESERVOIR
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 vacuum needed to main-
tain proper speed control operation. The vacuum res-
ervoir cannot be repaired and must be replaced if
faulty.
VEHICLE SPEED AND DISTANCE
The 4 speed automatic Transmission Control Mod-
ule (TCM) supplies the speed input to the PCM. The
PCM determines acceleration rates. The speed con-
trol software in the PCM uses vehicle speed and
acceleration to control to the set speed.
Vehicles with a 3 speed automatic or manual trans-
mission have a vehicle speed sensor (VSS) mounted
to an adapter near the transmission output shaft.
The sensor is driven through the adapter by a speed-
ometer pinion gear. The VSS pulse signal is moni-
tored by the PCM to determine vehicle speed and to
maintain speed control set speed. Refer to the appro-
priate Powertrain Diagnostic Procedures manual for
diagnosis and testing of this component. Refer to
group 14, Fuel System for Removal/Installation
DIAGNOSIS AND TESTING
ROAD TEST
Perform a vehicle road test to verify reports of
speed control system malfunction. The road test
should include attention to the speedometer. Speed-
ometer operation should be smooth and without flut-
ter at all speeds.
Flutter in the speedometer indicates a problem
which might cause surging in the speed control sys-
tem. The cause of any speedometer problems should
be corrected before proceeding. Refer to Group 8E,
Instrument Panel and Gauges for speedometer diag-
nosis.
If a road test verifies a surge following a set and
the speedometer operates properly see ªOvershoot/
Undershoot on speed control setº.
If a road test verifies an inoperative system, and
the speedometer operates properly, check for:
²A Diagnostic Trouble Code (DTC). If a DTC
exists, conduct tests per the Powertrain Diagnostic
Procedures service manual.
²A misadjusted brake (stop) lamp switch. This
could also cause an intermittent problem.
²Loose or corroded electrical connections at the
servo. Corrosion should be removed from electricalterminals and a light coating of Mopar Multipurpose
Grease, or equivalent, applied.
²Leaking vacuum reservoir.
²Loose or leaking vacuum hoses or connections.
²Defective one-way vacuum check valve.
²Secure attachment at both ends of the speed
control servo cable.
²Smooth operation of throttle linkage and throttle
body air valve.
²Conduct electrical test at PCM.
²Failed speed control servo. Do the servo vacuum
test.
CAUTION: When test probing for voltage or conti-
nuity at electrical connectors, care must be taken
not to damage connector, terminals or seals. If
these components are damaged, intermittent or
complete system failure may occur.
OVERSHOOT/UNDERSHOOT FOLLOWING SPEED
CONTROL SET
If the operator repeatedly presses and releases the
set button with their foot off of the accelerator (a ªlift
foot setº to begin speed control operation), the vehicle
may accelerate and exceed the desired set speed by
up to 5 MPH (8 km/h) and then decelerate to less
than the desired set speed before finally achieving
the desired set speed.
The Speed Control has an adaptive strategy that
compensates for vehicle-to-vehicle variations in speed
control cable lengths. When the speed control is set
with the vehicle operators foot off of the accelerator
pedal, the speed control thinks there is excessive
speed control cable slack and adapts. If the lift foot
sets are continually used, the speed control over-
shoot/undershoot condition will develop.
To ªunlearnº the overshoot/undershoot condition,
the vehicle operator has to press and release the set
button while maintaining the desired set speed with
the accelerator pedal (not decelerating or accelerat-
ing), and then turn the cruise control switch to the
OFF position (or press the CANCEL button if
equipped) after waiting 10 seconds. This procedure
must be performed approximately 10±15 times to
completely unlearn the overshoot/undershoot condi-
tion.
CHECKING FOR DIAGNOSTIC CODES
When trying to verify a speed control system elec-
tronic malfunction: Connect a DRB scan tool if avail-
able to the data link connector. The connector is
located at left side of the steering column, and at
lower edge of the panel.
(1) A speed control malfunction may occur without
a diagnostic code being indicated.
NSVEHICLE SPEED CONTROL SYSTEM 8H - 3
DESCRIPTION AND OPERATION (Continued)

Refer to Group 25, for further information and use-
age of the DRB scan tool and a more complete list of
Diagnostic Trouble Code.
SPEED CONTROL SLOWS DOWN BY ITSELF
Test vehicle speed sensor, refer to group 8E. If sen-
sor fails replace sensor, if it passes perform the fol-
lowing test:
(1) Perform the speed control switch test on the
DECEL switch, if it fails replace switch.
(2) If the switch passes, conduct the vacuum sup-
ply test.
(3) If it passes, conduct the servo vacuum test. If it
fails replace servo.
(4) If continuity, replace the PCM.
SPEED CONTROL ELECTRICAL TEST
Electronic speed control systems may be tested
using two different methods. One involves use of a
DRB. If this test method is desired, refer to the Pow-
ertrain Diagnostic Test Procedures for charging and
speed control system manual.The other test method uses a volt/ohm meter. The
volt/ohm meter method is described in the following
tests.
If any information is needed concerning wiring,
refer to Group 8W, Wiring Diagrams (Fig. 2).
CAUTION: When test probing for voltage or conti-
nuity at electrical connectors, care must be taken
not to damage connector, terminals, or seals. If
these components are damaged, intermittent or
complete system failure may occur.
When electrical connections are removed, corrosion
should be removed from electrical terminals and a
light coating of Mopar Multi-Purpose Grease, or
equivalent, applied. Inspect connectors for damage
terminals.
A poor connection can cause a complete or inter-
mittent malfunction and is also the only connection
in the circuit, that can not be tested. For this reason,
a loose connection may be misdiagnosed as a compo-
nent malfunction.
SPEED CONTROL DIAGNOSTIC TROUBLE CODES
Hex Code DRB Scan Tool Display Description of Diagnostic Trouble
Code
23 No Vehicle Speed Sensor Signal No vehicle distance (speed) sensor
signal detected during road load
conditions.
OF Speed Control Solenoid Circuits An open or shorted condition
detected in the Speed Control
vacuum or vent solenoid circuits.
56 MUX S/C Switch High Speed Control switch input above
the maximum acceptable voltage.
57 MUX S/C Switch Low Speed Control switch input below
the minimum acceptable voltage.
52 S/C Power Relay Or 12V Driver
CircuitMalfunction detected with power
feed to speed control servo solnoids.
Check Engine Lamp will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
8H - 4 VEHICLE SPEED CONTROL SYSTEMNS
DIAGNOSIS AND TESTING (Continued)