2005 CHRYSLER CARAVAN transmission

AUTOMATIC DAY / NIGHT
MIRROR
DESCRIPTION
An automatic dimming inside day/night rear view
mirror and an automatic dimming driver side outside
rear view mirror are available factory-installed
options on this model. Following is a general descrip-
tion of this optional equipment.
The automatic day/night mirror is able to automat-
ically change its reflectance. A thin layer of electro-
chromic material between two pieces of conductive
glass make up the face of the mirror. Two photocell
sensors are used to monitor light levels and adjust
the reflectance of the mirror to reduce the glare of
headlamps approaching the vehicle from the rear.
For removal procedures, (Refer to 23 - BODY/IN-
TERIOR/REAR VIEW MIRROR - REMOVAL).
OPERATION
The ambient photocell sensor faces forward, to
detect the outside light levels. A second sensor faces
rearward to detect the light level received through
the vehicles back window. When the difference
between the two light levels becomes too great (the
light level received at the rear of the mirror is much
higher than that at the front of the mirror), the mir-
ror begins to darken.
The mirror switch allows the driver a manual con-
trol of whether the automatic dimming feature is
operational. When AUTO is selected a small Light-
Emitting Diode (LED), to the right of the mirror
switch, is illuminated. The automatic dimming fea-
ture will only operate when the ignition switch is in
the On position. The mirror also senses the backup
lamp circuit, and will automatically disable its self-
dimming feature whenever the transmission gear
selector is in the Reverse position.
NOTE: The mirror always defaults to an ON state
upon ignition.
The driver side automatic dimming mirror is stan-
dard with the automatic dimming inside mirror. The
signal to control the dimming of that mirror is gen-
erated by the automatic day/night inside rear view
mirror circuitry. That signal is then delivered to the
driver side outside rear view mirror on a hard wired
circuit.
The automatic day/night mirror cannot be
repaired. If faulty or damaged, the entire inside rear
view mirror assembly must be replaced.
DIAGNOSIS AND TESTING
AUTOMATIC DAY / NIGHT MIRROR
For circuit descriptions and diagrams, refer to the
appropriate wiring information. The wiring informa-
tion includes wiring diagrams, proper wire and con-
nector repair procedures, details of wire harness
routing and retention, connector pin-out information
and location views for the various wire harness con-
nectors, splices and grounds.
(1) Check the fuse in the intelligent power module.
If OK, go to Step 2. If not OK, repair the shorted cir-
cuit or component as required and replace the faulty
fuse.
(2) Turn the ignition switch to the On position.
Check for battery voltage at the fuse in the intelli-
gent power module. If OK, go to Step 3. If not OK,
repair the open circuit to the ignition switch as
required.
(3) Unplug the wire harness connector from the
automatic day/night mirror. Check for battery voltage
at the fused ignition switch output circuit cavity of
the automatic day/night mirror wire harness connec-
tor. If OK, go to Step 4. If not OK, repair the open
circuit to the junction block as required.
(4) Turn the ignition switch to the Off position.
Check for continuity between the ground circuit cav-
ity of the automatic day/night mirror wire harness
connector and a good ground. There should be conti-
nuity. If OK, go to Step 5. If not OK, repair the cir-
cuit to ground as required.
(5) Turn the ignition switch to the On position. Set
the parking brake. Place the transmission gear selec-
tor lever in the Reverse position. Check for battery
voltage at the backup lamp switch output circuit cav-
ity of the automatic day/night mirror wire harness
connector. If voltage is present, reinstall the auto-
matic day/night mirror wire harness connector and
go to Step 6. If not OK, repair the open circuit as
required.
(6) Place the transmission gear selector lever in
the Neutral position. Place the automatic day/night
mirror switch in the On (LED in the switch is
lighted) position. Cover the forward facing ambient
photocell sensor to keep out any ambient light.
NOTE: The ambient photocell sensor must be cov-
ered completely, so that no light reaches the sen-
sor. Use a finger pressed tightly against the sensor,
or cover the sensor completely with electrical tape.
(7) Shine a light into the rearward facing head-
lamp photocell sensor. The automatic day/night mir-
ror should darken. The automatic day/night mirror
should darken within 2 minutes if testing for the
first time. For immediate response, turn the vehicle
8N - 28 POWER MIRRORSRS

(Refer to 8 - ELECTRICAL/HEATED SEATS -
DESCRIPTION) for more information on the heated
seat option. (Refer to 8 - ELECTRICAL/POWER
SEATS - DESCRIPTION - MEMORY SEAT SYS-
TEM) for more information on the memory seat sys-
tem.
The power seat system includes the following com-
ponents:
²Power seat recliners
²Power seat switches
²Power seat tracks
²Circuit breaker
The power seat system with memory and heated
seat options includes the following components:
²Power seat recliner
²Power seat switch
²Power seat track.
²Memory Seat Mirror Module (MSMM)
²Memory set switch
²Heated Seat Module (HSM)
²Heated seat switch
²Electronic Vehicle Information Center (EVIC)
MEMORY SYSTEM
The memory system is able to store and recall the
driver side power seat positions (including the power
recliner position), power adjustable pedal positions
and the driver outside mirror position for two driv-
ers. On vehicles equipped with a factory radio, the
memory system is also able to store and recall radio
station presets for two drivers. The memory system
also will store and recall the last station listened to
for each driver, even if it is not one of the preset sta-
tions.
The memory system will automatically return to
its preset settings when the corresponding numbered
button of the memory switch is depressed, or when
the doors are unlocked using the corresponding
Remote Keyless Entry (RKE) transmitter. A customer
programmable feature of the memory system allows
the RKE recall of memory features to be disabled, if
desired. This programmable feature is internal in the
Electronic Vehicle Information Center (EVIC) mod-
ule, which is located in the overhead console.
A Memory Seat Mirror Module (MSMM) is used to
control and integrate the many electronic functions
and features included in the memory seat and mirror
systems.
The memory system includes the following compo-
nents:
²Memory Seat Mirror Module (MSMM)
²Memory set switch
²Position potentiometers on the driver outside
side view mirror
²Position potentiometers on the power adjustable
pedal motor²Position potentiometers on the driver side power
seat track and power seat recliner motors
²Electronic Vehicle Information Center (EVIC)
²Radio receiver (if PCI data bus capable)
Certain functions of the memory system rely upon
resources shared with other electronic modules in the
vehicle over the Programmable Communications
Interface (PCI) data bus network. Initial diagnosis of
these electronic modules or the PCI data bus network
requires the use of a DRBIIItor equivalent scan tool
and the proper Diagnostic Procedures information. If
this method does not prove conclusive, the proper
wiring schematics and the service manual diagnostic
information are required.
The other electronic modules that may affect mem-
ory system operation are:
²Body Control Module (BCM)- (Refer to 8 -
ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/BODY CONTROL/CENTRAL TIMER MODUL
- DESCRIPTION) for additional information.
²Powertrain Control Module (PCM)- (Refer
to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES/POWERTRAIN CONTROL MODULE -
DESCRIPTION) for additional information.
²Transmission Control Module (TCM)- (Refer
to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES/TRANSMISSION CONTROL MODULE -
DESCRIPTION) for additional information.
(Refer to 8 - ELECTRICAL/HEATED SEATS -
DESCRIPTION) for additional information on the
heated seat system. (Refer to 8 - ELECTRICAL/
POWER LOCKS - DESCRIPTION) for additional
information on the RKE system.
OPERATION
POWER SEAT SYSTEM
The power seat system receives battery current
through fuse #22 in the Integrated Power Module
(IPM) and a circuit breaker under the front seats,
regardless of the ignition switch position.
When a power seat switch control knob or knobs
are actuated, a battery feed and a ground path are
applied through the switch contacts to the appropri-
ate power seat track adjuster motor. The selected
adjuster motor operates to move the seat track
through its drive unit in the selected direction until
the switch is released, or until the travel limit of the
seat track is reached. When the switch is moved in
the opposite direction, the battery feed and ground
path to the motor are reversed through the switch
contacts. This causes the adjuster motor to run in the
opposite direction.
No power seat switch should be held applied in any
direction after the seat track has reached its travel
limit. The power seat adjuster motor each contain a
8N - 32 POWER SEAT SYSTEMRS
POWER SEAT SYSTEM (Continued)

travel. This allows the power sliding door to stop and
reverse direction any time an obstruction is felt or
any of the command switches are operated (while
closing only). Battery voltage is supplied to the power
sliding door system through a 40 amp fuse, located in
the Integrated Power Module (IPM) assembly. The
child lockout switch prevents children from opening
or actuating the power sliding door system when
desired. In the unlikely event that the power sliding
door system develops a fault, the power sliding door
can still be operated manually from the interior or
exterior door handle, just like a standard manual
sliding door.
The power sliding door control module communi-
cates on the Programmable Communication Interface
(PCI) Data Bus Circuit. Therefore, the power sliding
door control module can generate and store its own
Diagnostic Trouble Codes (DTC). A diagnostic scan
tool, such as the DRB IIItis used to read and diag-
nose these trouble codes.
NOTE: It may be possible to generate Sliding Door
Diagnostic Trouble Codes during normal power
sliding door operation. Refer to the Body Diagnos-
tic Manual for a complete list of diagnostic routines.
For additional information, (Refer to 8 - ELECTRI-
CAL/POWER DOORS - OPERATION). Refer to the
appropriate wiring information for complete circuit
schematic or connector pin-out information.WARNING: BE CERTAIN TO READ ALL WARNINGS
AND CAUTIONS IN POWER SLIDING DOOR OPER-
ATION BEFORE ATTEMPTING ANY SERVICE OF
THE POWER SLIDING DOOR SYSTEM OR COMPO-
NENTS.
OPERATION
With the push of a power sliding door open/close
command switch (key fob, overhead console or B-pil-
lar mounted) a signal is sent out to the Body Control
Module (BCM). The BCM then sends a signal out on
the Programmable Communication Interface (PCI)
Data Bus circuit to the power sliding door module.
The power sliding door module then signals the
power sliding door latch to release the door to the
unlatched and movable position. The motor then
starts an open cycle.
During the door cycle, if the power sliding door
module detects sufficient resistance to door travel,
such as an obstruction in the door's path, the power
sliding door module will immediately stop door move-
ment and reverse door travel to the full open or
closed position. The ability for the power sliding door
module to detect resistance to door travel is accom-
plished by hall effect sensors detecting the door
motor speed.
The power sliding door control module has the abil-
ity to learn. Anytime a door is opened or closed using
the power sliding door system the module learns
from its cycle. If a replacement power sliding door
component is installed or a door adjustment is made,
the module must re-learn the effort required to open
or close the door. A learn cycle can be performed with
a complete cycle of the door, using any one of the
command switches or with the DRB IIIt, or equiva-
lent scan tool. (Refer to 8 - ELECTRICAL/POWER
DOORS - STANDARD PROCEDURE - LEARN
CYCLE) for detailed instructions.
The power sliding door system is designed with a
number of system inhibitors. These inhibitors are
necessary for safety and/or feasibility of the power
sliding door system. The power sliding door system
inhibitors are:
²The power sliding door must be in thefullopen
or closed position in order for the power sliding door
system to start a cycle. If the door is not in this posi-
tion (based on the input from the full open, pawl or
ratchet switches) the door control module will not
respond to command switch inputs.
²The transmission must be inpark or neutral
in order for the power sliding door system to start a
cycle.
²The child lockout switch must be in the
ªUNLOCKEDº position in order for the power sliding
door systems B-pillar switches to function.
Fig. 1 KEY FOB
1 - LEFT SLIDING DOOR SWITCH
2 - RIGHT SLIDING DOOR SWITCH
3 - LIFTGATE SWITCH
RSPOWER SLIDING DOOR SYSTEM8N-41
POWER SLIDING DOOR SYSTEM (Continued)

²Occupant Classification Module- Vehicles
equipped with the Occupant Classification System
(OCS) include an Occupant Classification Module
(OCM) which is secured to a stamped steel mounting
bracket on the underside of the passenger side front
seat cushion frame.
²Occupant Restraint Controller- The Occu-
pant Restraint Controller (ORC) is also sometimes
referred to as the Airbag Control Module (ACM). The
ORC is located on a mount on the floor transmission
tunnel just underneath the instrument panel center
stack (Fig. 3).
²Passenger Airbag- The passenger airbag is
located on the instrument panel, beneath the instru-
ment panel top pad and above the glove box on the
passenger side of the vehicle (Fig. 3).
²Passenger Airbag Disabled (PAD) Indicator
- Vehicles equipped with the Occupant Classification
System (OCS) include a passenger airbag disabled
(PAD) indicator which is located in the instrument
panel center stack (Fig. 3).
²Passenger Knee Blocker- The passenger knee
blocker is a structural reinforcement that is integral
to and concealed within the glove box door (Fig. 3).
²Seat Belt Tensioner- A seat belt tensioner is
integral to both front seat belt buckles. The seat belt
buckles are secured to the inner seat frame sides,
beneath a cushion trim panel.
²Seat Weight Bladder and Pressure Sensor
Assembly- Vehicles equipped with the Occupant
Classification System (OCS) include a seat weight
bladder that is sandwiched between an insulator pad
on the top of the passenger side front seat pan and
the seat cushion foam padding. A short hose connects
the bladder to a pressure sensor which is secured to
the Occupant Classification Module (OCM) mounting
bracket on the underside of the passenger side front
seat cushion frame.
²Side Impact Sensors- Six side impact sensors
are used on vehicles equipped with the curtain air-
bags, three left side and three right side. The first
row side impact sensor is located in the B-pillar, just
above the front seat belt retractor. The second row
side impact sensor is located in the sliding side door
track opening, just in front of the C-pillar. The third
row side impact sensor is located behind the quarter
trim panel, above the rear tire wheel well, between
the C and D-pillars.
The ORC, the OCM, and the cluster each contain a
microprocessor and programming that allow them to
communicate with each other using the Programma-
ble Communications Interface (PCI) data bus net-
work. This method of communication is used by the
ORC for control of the airbag indicators.OPERATION
ACTIVE RESTRAINTS
The primary passenger restraints in this or any
other vehicle are the seat belts and child restraint
anchors. Seat belts and child restraint anchors are
referred to as an active restraint because the vehicle
occupants are required to physically fasten and prop-
erly adjust these restraints in order to benefit from
them. See the owner's manual in the vehicle glove
box for more information on the features, use and
operation of all of the active restraints.
PASSIVE RESTRAINTS
The passive restraints are referred to as a supple-
mental restraint system because they were designed
and are intended to enhance the protection for the
occupants of the vehicleONLYwhen used in con-
junction with the seat belts. They are referred to as
passive restraints because the vehicle occupants are
not required to do anything to make them operate;
however, the vehicle occupants must be wearing their
seat belts in order to obtain the maximum safety
benefit from the supplemental restraint system.
The supplemental restraint system electrical cir-
cuits are continuously monitored and controlled by a
microprocessor and software contained within the
Occupant Restraint Controller (ORC). An airbag indi-
cator in the ElectroMechanical Instrument Cluster
(EMIC) illuminates for about seven seconds as a bulb
test each time the ignition switch is turned to the
ON or START positions. Following the bulb test, the
airbag indicator is turned ON or OFF by the ORC to
indicate the status of the supplemental restraint sys-
tem. If the airbag indicator comes ON at any time
other than during the bulb test, it indicates that
there is a problem in the supplemental restraint sys-
tem electrical circuits. Such a problem may cause air-
bags not to deploy when required, or to deploy when
not required.
Deployment of the supplemental restraints
depends upon the angle and severity of an impact.
Deployment is not based upon vehicle speed; rather,
deployment is based upon the rate of deceleration as
measured by the forces of gravity (G force) upon the
impact sensors. When an impact is severe enough,
the microprocessor in the ORC signals the inflator of
the appropriate airbag units to deploy their airbag
cushions. The front seat belt tensioners are provided
with a deployment signal by the ORC in conjunction
with the front airbags. During a frontal vehicle
impact, the knee blockers work in concert with prop-
erly fastened and adjusted seat belts to restrain both
the driver and the front seat passenger in the proper
position for an airbag deployment. The knee blockers
also absorb and distribute the crash energy from the
8O - 4 RESTRAINTSRS
RESTRAINTS (Continued)

The ORC is secured with screws to a stamped steel
mounting bracket welded onto the top of the floor
panel transmission tunnel just behind and under-
neath the instrument panel center stack in the pas-
senger compartment of the vehicle (Fig. 38).
Concealed within a hollow in the center of the die
cast aluminum ORC housing is the electronic cir-
cuitry of the ORC which includes a microprocessor,
an electronic impact sensor, an electronic safing sen-
sor, and an energy storage capacitor. A stamped
metal cover plate is secured to the bottom of the
ORC housing with four screws to enclose and protect
the internal electronic circuitry and components.
An arrow printed on the label on the top of the
ORC housing provides a visual verification of the
proper orientation of the unit, and should always be
pointed toward the front of the vehicle. The ORC
housing has integral mounting flanges. the ORC has
two molded plastic electrical connectors that exits the
right facing side of the ORC housing. These terminal
pins connect the ORC to the vehicle electrical system.
The impact sensor and safing sensor internal to
the ORC are calibrated for the specific vehicle, and
are only serviced as a unit with the ORC. In addi-
tion, there are unique versions of the ORC for vehi-
cles with or without curtain airbags. The ORC cannot
be repaired or adjusted and, if damaged or faulty, it
must be replaced.
OPERATION
The microprocessor in the Occupant Restraint Con-
troller (ORC) contains the supplemental restraint
system logic circuits and controls all of the supple-
mental restraint system components. The ORC uses
On-Board Diagnostics (OBD) and can communicatewith other electronic modules in the vehicle as well
as with the diagnostic scan tool using the Program-
mable Communication Interface (PCI) data bus. This
method of communication is used for control of the
airbag indicator in the ElectroMechanical Instrument
Cluster (EMIC) and for supplemental restraint sys-
tem diagnosis and testing through the 16-way Data
Link Connector (DLC) located on the driver side
lower edge of the instrument panel.
The ORC microprocessor continuously monitors all
of the supplemental restraint system electrical cir-
cuits to determine the system readiness. If the ORC
detects a monitored system fault, it sets an active
and stored Diagnostic Trouble Code (DTC) and sends
electronic messages to the EMIC over the PCI data
bus to turn on the airbag indicator. An active fault
only remains for the duration of the fault, or in some
cases for the duration of the current ignition switch
cycle, while a stored fault causes a DTC to be stored
in memory by the ORC. For some DTC's, if a fault
does not recur for a number of ignition cycles, the
ORC will automatically erase the stored DTC. For
other internal faults, the stored DTC is latched for-
ever.
On models equipped with the Occupant Classifica-
tion System (OCS), the ORC communicates with the
Occupant Classification Module (OCM) over the PCI
data bus. The ORC will internally disable the pas-
senger airbag and seat belt tensioner deployment cir-
cuits if the OCM detects that the passenger side
front seat is unoccupied or that it is occupied by a
load that is inappropriate for an airbag deployment.
The ORC also provides a control output to the Pas-
senger Airbag Disabled (PAD) indicator through the
passenger airbag indicator driver circuit. The OCM
notifies the ORC when it has detected a monitored
system fault and stored a DTC in its memory for any
faulty OCS component or circuit, then the ORC sets
a DTC and controls the airbag indicator operation
accordingly.
The ORC receives battery current through two cir-
cuits; a fused ignition switch output (RUN) circuit
through a fuse in the Junction Block (JB), and a
fused ignition switch output (RUN/START) circuit
through a second fuse in the JB. The ORC receives
ground through a ground circuit of the instrument
panel wire harness. These connections allow the ORC
to be operational whenever the ignition switch is in
the START or ON positions.
The ORC also contains an energy-storage capacitor.
When the ignition switch is in the START or ON
positions, this capacitor is continually being charged
with enough electrical energy to deploy the front sup-
plemental restraint components for up to one second
following a battery disconnect or failure. The purpose
of the capacitor is to provide backup supplemental
Fig. 38 ORC LOCATION
1 - ORC ELECTRICAL CONNECTORS
2 - ORC
3 - ORC MOUNTING SCREWS
8O - 28 RESTRAINTSRS
OCCUPANT RESTRAINT CONTROLLER (Continued)

SPEED CONTROL
TABLE OF CONTENTS
page page
SPEED CONTROL
DESCRIPTION..........................1
OPERATION
OPERATION..........................1
OPERATION - INTERACTIVE SPEED
CONTROL (4 Speed EATX Only)...........2
DIAGNOSIS AND TESTING - ROAD TEST.....3
SPECIFICATIONS - TORQUE...............3
CABLE
DESCRIPTION..........................4
OPERATION............................4
REMOVAL.............................4
INSTALLATION..........................4
SERVO
DESCRIPTION..........................4OPERATION............................4
REMOVAL.............................4
INSTALLATION..........................4
SWITCH
DESCRIPTION..........................5
OPERATION............................5
REMOVAL.............................5
INSTALLATION..........................6
VACUUM RESERVOIR
DESCRIPTION..........................6
OPERATION............................6
REMOVAL.............................6
INSTALLATION..........................6
SPEED CONTROL
DESCRIPTION
The speed control system is electronically con-
trolled and vacuum operated. The electronic control
is integrated into the Powertrain Control Module.
The controls are located on the steering wheel. The
ON/OFF, and SET buttons are located on the left side
of the airbag module. The RESUME/ACCEL, CAN-
CEL and COAST buttons are located on the right
side of the airbag module (Fig. 1).The system is designed to operate at speeds above
30 mph (48 km/h).
WARNING: THE USE OF SPEED CONTROL IS NOT
RECOMMENDED WHEN DRIVING CONDITIONS DO
NOT PERMIT MAINTAINING A CONSTANT SPEED,
SUCH AS IN HEAVY TRAFFIC OR ON ROADS THAT
ARE WINDING, ICY, SNOW COVERED, OR SLIP-
PERY.
OPERATION
OPERATION
When speed control is activated 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 and release the SET switch while the vehicle
is moving at a speed between 25 and 85 mph. In
order for the speed control to engage, the brakes can-
not be applied, nor can the gear selector be indicat-
ing the transmission is in Park or Neutral (ATX) or
1st/2nd gear (MTX). The speed control can be disen-
gaged manually by:
²Stepping on the brake pedal
²Depressing the OFF switch
²Depressing the CANCEL switch.
²Depressing the clutch pedal
²Operating in 1st or 2nd gear (autostick, if
equipped)
Fig. 1 SPEED CONTROL SWITCHES - Typical
RSSPEED CONTROL8P-1

NOTE: Turning the system off by 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 disengage for any of the following condi-
tions:
²An indication of Park or Neutral
²A rapid increase rpm (indicates that the clutch
has been disengaged)
²Excessive engine rpm (indicates that the trans-
mission may be in a low gear)
²The speed 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 speed 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 greater than 20 mph over
the set speed.
²Autostick shifts into 1st or 2nd gear (autostick,
if equipped)
Once the speed control has been disengaged,
depressing the RESUME switch when speed is
greater than 20 mph allows the vehicle to resume
control to the target speed that was stored in the
PCM.
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 switch is released. The PCM also
has a9tap-up9feature in which target speed
increases by 2 mph for each momentary switch acti-
vation of the ACCEL switch. The PCM also provides
a means to decelerate to a new lower target speed
without disengaging speed control. Depress and hold
the COAST switch until the desired speed is reached,
then release the switch.
The PCM also has a ªTap Downº feature in which
target speed decreases at 1 mph for each momentary
switch activation of the coast switch.
OPERATION - INTERACTIVE SPEED CONTROL
(4 Speed EATX Only)
Interactive means that communication between the
PCM and the TCM is taking place, this communica-
tion is internal to the PCM on NGC vehicles. Inter-
active speed control avoids unnecessary shifting for
smoother, quieter operation and when downshifts are
required, makes the shifts smoother.
CLIMBING A GRADE
DESCRIPTION
When climbing a grade the interactive speed con-
trol tries to maintain the set speed by increasing thethrottle opening, while inhibiting/delaying down-
shifts.
OPERATION
If opening the throttle alone cannot maintain the
set speed and the vehicle speed drops more than
three mph below the set speed, the transmission will
downshift to third gear. If the vehicle continues to
lose speed, by more than 6 mph, the transmission
will downshift again to maintain the set speed. After
the vehicle encounters a less-steep grade, or has
crested the grade (reduced the load on the power-
train) and can maintain the set speed at a reduced
throttle position, the transmission will upshift, as
appropriate, until the set speed can be maintained in
Overdrive.
GRADE HUNTING
DESCRIPTION
All vehicles equipped with a four speed automatic
transmission have a grade hunting feature for the
2nd to 3rd gear upshift and the 3rd to Overdrive
upshift.
OPERATION
The PCM on NGC vehicles identifies the power-
train loading conditions and selects the proper gear
to maintain the current vehicle speed. Under moder-
ate loading conditions the transaxle will stay in 3rd
gear until the top of the grade is reached or the pow-
ertrain loading is reduced.
If powertrain loading is severe, the transaxle may
shift into 2nd gear and remain there until power-
train loading is reduced, then a 2nd to 3rd gear
upshift will be scheduled. Grade hunting features
always operate regardless of whether or not the
interactive speed control is engaged.If the interac-
tive speed control is not engaged and power-
train loading is not reduced, the driver may
have to completely lift off of the throttle before
an upshift will occur. If the driver does lift off the
throttle to induce an upshift under these conditions,
vehicle speed will reduce and the Overdrive to 3rd
and 3rd to 2nd gear downshifts will reoccur when the
throttle is reapplied. If grade hunting is repeatedly
induced by the driver, transaxle damage may result.
AUTOMATIC SPEED CONTROL OVERSPEED
REDUCTION
DESCRIPTION
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.
8P - 2 SPEED CONTROLRS
SPEED CONTROL (Continued)

OPERATION
The PCM on NGC vehicles first senses that the
speed control is set. If the set speed is exceeded by
more than 4 mph (6.5 km/hr) and the throttle is
closed, the PCM on NGC vehicles causes the trans-
axle to downshift to THIRD gear. After downshifting,
the automatic speed control resumes normal opera-
tion. To ensure that an upshift is appropriate after
the set speed is reached, the PCM on NGC vehicles
waits until the speed control system opens the throt-
tle at least 6 degrees before upshifting to OVER-
DRIVE again.
If the driver applies the brakes, canceling auto-
matic speed control operation with the transaxle still
in THIRD gear, the PCM on NGC vehicles maintains
this gear until the driver opens the throttle at least 6
degrees to avoid an inappropriate upshift. The
upshift is also delayed for 2.5 seconds after reaching
the 6 degrees throttle opening in anticipation that
the driver might open the throttle enough to require
THIRD gear. This will avoid unnecessary and dis-
turbing transmission 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.
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 the Instru-
ment Cluster for speedometer diagnosis.
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 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 electrical
terminals 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.
SPECIFICATIONS - TORQUE
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Servo Mounting Bracket
Nuts14 10.3 123.9
Servo Mounting Bracket
Bolts14 10.3 123.9
Servo Mounting Nuts 6.7 60
RSSPEED CONTROL8P-3
SPEED CONTROL (Continued)