1996 CHRYSLER VOYAGER servo

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)

SERVO VACUUM TEST
(1) Turn ignition switch to the ON position with-
out starting engine. Activate speed control ON
switch.
(2) Disconnect the four-way electrical connector
and the vacuum harness at the servo (Fig. 3).
(3) Connect a jumper wire from Pin 3 of the servo
to Pin 3 of the wire connector.
(4) Ground Pins 2 and 4 in the servo. Do not con-
nect pin 1.
(5) Connect a hand held vacuum pump to the vac-
uum nipple and apply 10 - 15 inches of vacuum.
(6) If servo pulls cable, replace servo.
(7) Ground Pin 1 on servo.
(8) Check that the throttle cable pulls in and holds
as long as the vacuum pump is connected. After one
minute, check if cable is still holding. If cable does
not hold replace the servo.
(9) Disconnect jumper from pin 3. Cable should
return to rest position. If not, replace servo.
(10) Connect 4 way electrical connector and vac-
uum harness to servo.
SPEED CONTROL SWITCH TEST
Refer to the appropriate Powertrain Diagnostic
Manual for switch test valves.
STOP LAMP SWITCH TEST
(1) Remove the stop lamp switch refer to Stop
Switch Removal/Installation in this section. Discon-
nect connector from stop lamp switch (Fig. 4). Using
an ohmmeter, switch continuity may be checked as
follows:
(2) With switch plunger released, there should be
continuity between Pin 5 and Pin 6.(3) With switch plunger depressed, there should be
continuity:
²Between Pin 1 and Pin 2.
²Between Pin 3 and Pin 4.
(4) If the above results are not obtained, the stop
lamp switch is defective or out of adjustment.
(5) Stop lamp switch adjustment is detailed in
Group 5, Brakes.
ELECTRICAL TESTS AT POWERTRAIN CONTROL
MODULE
(1) Unplug the GRAY 40-way connector from the
Powertrain Control Module (PCM), (Fig. 5).
(2) Remove both steering wheel speed control
switches and disconnect the wire connectors.
Fig. 3 Servo Harness Connector
Fig. 4 Stop Lamp Wiring
Fig. 5 Powertrain Control Module Location
8H - 6 VEHICLE SPEED CONTROL SYSTEMNS
DIAGNOSIS AND TESTING (Continued)

(a) Using an ohmmeter, check for continuity
between cavity 41 of the PCM connector and cavity
1 of each speed control switch connector (Fig. 6).
(b) If no continuity, repair as necessary.
(c) Using an ohmmeter, check for continuity
between cavity 41 of the PCM connector and
ground.
(d) If continuity, repair as necessary.
(e) If no continuity, perform the Switch Test.
(f) Plug GRAY 40 way connector into PCM.
(g) Plug switch connectors back into switches.
(3) Unplug speed control servo electrical connector.
(4) Place ignition switch in the ON position and
turn on the speed control system, for the following
tests.
(a) Using a voltmeter, measure voltage from cav-
ity 3 of servo connector to ground. Voltmeter
should read ignition voltage. If voltage is low, skip
to Step 7.
(b) Turn speed control and ignition switch OFF.
Using an ohmmeter, place positive lead on pin 3
and negative lead on pin 4 on the speed control
servo. Check continuity from pin 3 to pin 4.
(c) If no continuity, replace the speed control
servo. If continuity is greater than 49 ohms, clean
terminals.
(d) Using an ohmmeter, place positive lead on
pin 3 and negative lead on pin 2 on the speed con-
trol servo. Check continuity from pin 3 to pin 2.
(e) If no continuity, replace the speed control
servo. If continuity is greater than 49 ohms, clean
terminals.
(f) Using an ohmmeter, place positive lead on
pin 3 and negative lead on pin 1 on the speed con-
trol servo. Check continuity from pin 3 to pin 1.
(g) If no continuity, replace the speed control
servo. If continuity is greater than 49 ohms, clean
terminals.
(h) Using an ohmmeter at the servo connector,
place positive lead on cavity 4 and negative lead on
ground. Check continuity from cavity 4 to ground.
If no continuity, repair open circuit.
(i) Unplug 2 40-way PCM connectors.(j) Using an ohmmeter, check continuity from
cavity 1 of servo connector to cavity 56 (2.4, 3.3,
3.8L) or cavity 78 (3.0L) on PCM connector. If no
continuity, repair open circuit.
(k) Using an ohmmeter, check continuity from
cavity 1 of servo connector to ground. If continuity,
repair as necessary.
(l) If continuity is OK, check continuity from
cavity 2 of servo connector to cavity 80 of PCM
connector. If no continuity, repair open circuit.
(m) Using an ohmmeter, check continuity from
cavity 2 of servo connector to ground. If continuity,
repair as necessary.
(n) Using an ohmmeter, check continuity from
cavity 1 of servo connector to cavity 2 of servo con-
nector. If continuity, repair as necessary.
(o) Reconnect the 4 way connector to servo.
(5) Using an ohmmeter, check continuity from cav-
ity 62 of the PCM connector to ground. If continuity
is OK with brake pedal in unpressed position, pro-
ceed to Step 6.
(a) If no continuity, perform the Stop Lamp
switch test. Replace or adjust switch as required.
(b) If switch passes test, check continuity from
cavity 62 of the PCM connector to cavity 1 of the
stop lamp switch connector. Repair open circuit as
required.
(c) If continuity is OK between cavity 62 and
cavity 1, repair open circuit between cavity 2 of the
stop lamp switch connector and ground.
(6) Using an ohmmeter, check continuity from cav-
ity 76 on PCM connector to ground with the trans-
mission in drive. If continuity, test TRS/ Park-
Neutral switch and switch wiring.
(7) Turn speed control and ignition switch OFF.
(8) Unplug the BLACK 40-way connector from the
Powertrain Control Module (PCM).
(9) Using an ohmmeter, check continuity from cav-
ity 3 of servo connector to cavity 5 on the PCM con-
nector.
(a) If no continuity, skip to Step 10.
(b) If continuity is OK, check continuity from
pin 5 of PCM connector to ground. If continuity,
repair short to ground. If no contunity, replace
PCM. Jump to Step 11.
(10) Remove stop lamp switch and conduct Stop
Lamp Switch Test. If test fails, adjust or replace as
necessary.
(a) If switch passes, measure continuity from
cavity 4 of stop lamp switch connector to cavity 3
of servo connector. Repair open circuit if necessary.
(b) If continuity is OK, measure continuity from
cavity 3 of stop lamp switch to cavity 5 of PCM
connector. Repair open circuit as necessary.
(11) Install PCM connectors onto PCM and speed
control servo connector to servo.
Fig. 6 PCM 40ÐWay Connectors
NSVEHICLE SPEED CONTROL SYSTEM 8H - 7
DIAGNOSIS AND TESTING (Continued)

VACUUM SUPPLY TEST
(1) Disconnect vacuum hose at the servo and
install a vacuum gauge in the hose (Fig. 7).
(2) Start engine and observe gauge at idle. Vac-
uum gauge should read at least ten inches of mer-
cury. Shut off engine, the vacuum should continue to
hold 10 inches of mercury.
(3) If vacuum does not meet this requirement,
check and correct the following vacuum leaks in the
vacuum lines, check valve, vacuum reservoir or poor
engine performance.
VEHICLE SPEED SENSOR
For diagnosis and testing of the Vehicle Speed Sen-
sor (VSS), refer to the appropriate Powertrain Diag-
nostic Procedures service manual. Also refer to the
DRB scan tool.
REMOVAL AND INSTALLATION
SPEED CONTROL SERVO
REMOVAL
(1) Release hood latch and open hood.
(2) On vehicles with 3.3/3.8 L engine, remove air
cleaner resonator. Refer to Group 14, Fuel System for
proper procedure.
(3) Disconnect the throttle and speed control cable
ends from throttle body (Fig. 8).
(4) Depress lock tabs holding speed control cable
casing to cable mount bracket (Fig. 9).(5) Disconnect vacuum line from nipple on air
intake plenum.
(6) Remove tie wrap holding vacuum line, throttle
cable, and speed control cable together.
(7) Remove bolt holding speed control servo to side
of battery tray/vacuum reservoir (Fig. 10).
(8) Remove speed control servo from battery tray.
(9) Disconnect wire connector from speed control
servo.
(10) Disconnect vacuum line from speed control
servo that leads to the battery tray/vacuum reservoir.
(11) Remove speed control servo.
Fig. 7 Vacuum Gauge Test
Fig. 8 Speed Control Cable End
Fig. 9 Speed Control Cable Case and Vacuum
LineÐTypical
8H - 8 VEHICLE SPEED CONTROL SYSTEMNS
DIAGNOSIS AND TESTING (Continued)

INSTALLATION
Transfer speed control cable to replacement speed
control servo. Reverse the preceding operation.
SPEED CONTROL SWITCHES
REMOVAL
(1) Release hood latch and open hood.
(2) Disconnect battery negative cable.
(3) Remove airbag/horn pad from steering wheel,
refer to Group 8M, Restraint Systems for proper pro-
cedures.
(4) Disconnect wire connector from horn switch,
airbag, and speed control switches.
(5) Remove screws holding speed control switch to
airbag/horn pad (Fig. 11).
(6) Separate speed control switch from airbag/horn
pad.
INSTALLATION
Reverse the preceding operation.
STOP LAMP SWITCH
REMOVAL
Remove the switch from the bracket by depressing
the brake pedal and rotating the switch in a counter-
clockwise direction approximately 30 degrees. Pull
the switch rearward and remove from bracket. Dis-
connect wiring harness connector.
INSTALLATION
Before installing the switch, reset the adjustable
switch plunger by pulling on the plunger head until
the plunger reaches the end of its travel. A ratchet-
ing sound will be heard during this procedure.
Connect the wiring harness to the switch. Mount
the switch into the bracket by holding the switch
with the plunger facing forward in car. There is an
index key on the switch that mates with the bracket
slot at the top of the square hole. Align key and push
switch into square hole in bracket while depressing
the brake pedal. Once the switch is seated in the
hole, rotate clockwise approximately 30 degrees to
lock into place. The switch will automatically adjust
when the pedal is released. Pull back on the pedal to
assure correct adjustment.
SPEED CONTROL CABLE
REMOVAL
(1) Release hood latch and open hood.
(2) On vehicles with 3.3/3.8 L engine, remove air
cleaner resonator. Refer to Group 14, Fuel System for
proper procedure.
(3) Disconnect throttle and speed control cable
ends from throttle body (Fig. 8).
(4) Depress lock tabs holding speed control cable
casing to cable mount bracket (Fig. 12).
(5) Remove tie wrap holding vacuum line, throttle
cable, and speed control cable together.
(6) Remove nuts holding speed control cable case
to servo.
(7) Remove cable case from servo.
(8) Remove hairpin clip holding cable end to servo
diaphragm (Fig. 12).
(9) Remove speed control cable.
INSTALLATION
Reverse the preceding operation.
POWERTRAIN CONTROL MODULE
For Removal/Installation refer to Powertrain Con-
trol Module in Group 14, Fuel Injection System.
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
Fig. 10 Speed Control Servo
Fig. 11 Speed Control Switches
NSVEHICLE SPEED CONTROL SYSTEM 8H - 9
REMOVAL AND INSTALLATION (Continued)

STEP IS NOT DONE A DIAGONSTIC TROUBLE
CODE (DTC) MAY BE SET.
VACUUM RESEROIR
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove battery, Refer to Group 8B, for Battery
Removal/Installation
(3) Remove battery tray.
(4) Disconnect vacuum hoses from vacuum reser-
voir
INSTALLATION
(1) Connect vacuum hoses to vacuum reservoir.
(2) Install battery tray
(3) Install battery, Refer to Group 8B, for Battery
Removal/Installation.
(4) Connect negative cable to battery.
VEHICLE SPEED SENSOR
For Removal/Installation, refer to Vehicle Speed
Sensor in Group 14, Fuel Injections.
Fig. 12 Speed Control Cable
8H - 10 VEHICLE SPEED CONTROL SYSTEMNS
REMOVAL AND INSTALLATION (Continued)

VEHICLE SPEED CONTROL SYSTEM
CONTENTS
page
GENERAL INFORMATION
INTRODUCTION........................ 1
GENERAL INFORMATION
INTRODUCTION
This group covers both Left-Hand Drive (LHD) and
Right-Hand Drive (RHD) versions of this model.
Whenever feasible, the RHD versions of affected
vehicle components have been constructed as mirror-
image of the LHD versions. While most of the illus-
trations used in this group represent only the LHD
version, the diagnostic and service procedures out-
lined can generally be applied to either version.
Exceptions to this rule have been clearly identified as
LHD or RHD, if a special illustration or procedure
was/is required.
The speed control system used with the 2.5L diesel
engine is basically identical to the system used with
gasoline powered engines. Features unique to the
diesel engine will be covered in this section.
²Models equipped with the 2.5L diesel engine do
not use a vacuum reservoir to retain engine vacuum
for speed control operation. There are no vaccum-op-
erated speed control servos used in vehicles with the
2.5L diesel engine.
²The range of the speed control system operation
is restricted to speeds between 56 km/h (35 MPH) to
145 km/h (90 MPH).
²Inputs to the MSA that allow speed control oper-
ation are from the vehicle speed sensor and the
Speed Control Switch.²Two separate speed control switch modules are
mounted on the steering wheel to the left and right
side of the driver's airbag module. Switch features
are:
a. Within the two switch modules, fivemomen-
tarycontact switches, supporting seven different
speed control functions are used.
b. The outputs from these switches are filtered
into one input. The MSA determines which output
has been applied throughresistive multiplexing.
The input circuit voltage is measured by the MSA
to determine which switch function has been
selected.
c. A speed control indicator lamp, located on the
instrument panel cluster is energized by the MSA
via the CCD Bus. This occurs when speed control
system power has been turned ON, and the engine
is running.
d. The two switch modules are labeled: ON/OFF,
SET, RESUME/ACCEL, CANCEL and COAST.
Refer to the owner's manual for more information
on speed control switch functions and setting pro-
cedures. The individual switches cannot be
repaired. If one individual switch fails, the switch
module must be replaced.
NS/GSVEHICLE SPEED CONTROL SYSTEM 8H - 1