clutch CHRYSLER CARAVAN 2002 Repair Manual

INSPECTION
Before removing any unit from the starting system
for repair or diagnosis, perform the following inspec-
tions:
²Battery- Visually inspect the battery for indi-
cations of physical damage and loose or corroded
cable connections. Determine the state-of-charge and
cranking capacity of the battery. Charge or replace
the battery, if required. Refer to the Battery section
for more information.
²Ignition Switch- Visually inspect the ignition
switch for indications of physical damage and loose
or corroded wire harness connections.
²Transmission Range Sensor- Visually inspect
the transmission range sensor for indications of phys-
ical damage and loose or corroded wire harness con-
nections.
²Starter Relay- Visually inspect the starter
relay for indications of physical damage and loose or
corroded wire harness connections.
²Starter- Visually inspect the starter for indica-
tions of physical damage and loose or corroded wire
harness connections.
²Starter Solenoid- Visually inspect the starter
solenoid for indications of physical damage and loose
or corroded wire harness connections.
²Wiring- Visually inspect the wire harness for
damage. Repair or replace any faulty wiring, as
required. Check for loose or corroded wire harness
connections at main engine ground and remote jump
post.
²Power Distribution Center (PDC)- Visually
inspect the B+ connections at the PDC for physical
damage and loose or corroded harness connections.
Fig. 1 STARTING SYSTEM SCHEMATIC
1 - SOLENOID TERMINAL
2 - STARTER SOLENOID
3 - STARTER MOTOR
4 - STARTER RELAY CONNECTOR
5 - PCM
6 - GROUND CIRCUIT
7 - TRANSMISSION RANGE SENSOR/PARK/NEUTRAL SENSE
8 - IGNITION SWITCH
9 - IGNITION FEED
10 - BATTERY
11 - BATTERY RELAY FEED
12 - POSITIVE CABLE
13 - NEGATIVE CABLE
14 - CLUTCH INTERLOCK SWITCH (MTX ONLY)
8Fa - 32 STARTINGRG
STARTING (Continued)
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STARTING SYSTEM DIAGNOSIS
CONDITION POSSIBLE CAUSE CORRECTION
STARTER FAILS
TO ENGAGE.1. BATTERY
DISCHARGED OR
FAULTY.1. REFER TO THE BATTERY SECTION FOR MORE
INFORMATION. CHARGE OR REPLACE BATTERY, IF
REQUIRED.
2. STARTING CIRCUIT
WIRING FAULTY.2. REFER TO FEED CIRCUIT RESISTANCE TEST AND FEED
CIRCUIT TEST IN THIS SECTION.
3. STARTER RELAY
FAULTY.3. REFER TO RELAY TEST, IN THIS SECTION. REPLACE
RELAY, IF NECESSARY.
4. IGNITION SWITCH
FAULTY.4. REFER TO IGNITION SWITCH TEST, IN THE STEERING
SECTION OR 8 WIRING DIAGRAMS. REPLACE SWITCH, IF
NECESSARY.
5. PARK/NEUTRAL
POSITION SWITCH
(AUTO TRANS) FAULTY
OR MIS-ADJUSTED.5. REFER PARK/NEUTRAL POSITION SWITCH TEST, IN THE
TRANSAXLE. SECTION FOR MORE INFORMATION. REPLACE
SWITCH, IF NECESSARY.
6. CLUTCH PEDAL
POSITION SWITCH
(MAN TRANS) FAULTY.6. REFER TO CLUTCH PEDAL POSITION SWITCH TEST, IN
THE CLUTCH. SECTION. REPLACE SWITCH, IF NECESSARY.
7. STARTER SOLENOID
FAULTY.7. REFER TO SOLENOID TEST, IN THIS SECTION. REPLACE
STARTER ASSEMBLY, IF NECESSARY.
8. STARTER ASSEMBLY
FAULTY.8. IF ALL OTHER STARTING SYSTEM COMPONENTS AND
CIRCUITS CHECK OK, REPLACE STARTER ASSEMBLY.
9. FAULTY TEETH ON
RING GEAR.9. ROTATE FLYWHEEL 360É, AND INSPECT TEETH AND RING
GEAR REPLACED IF DAMAGED.
10. PCM DOUBLE
START OVERRIDE
OUTPUT FAILURE.10. REFER TO PCM DIAGNOSTIC. CHECK FOR CONTINUITY
BETWEEN PCM AND TERMINAL 85. REPAIR OPEN CIRCUIT
AS REQUIRED. IF OK, PCM MAY BE DEFECTIVE.
STARTER
ENGAGES,
FAILS TO TURN
ENGINE.1. BATTERY
DISCHARGED OR
FAULTY.1. REFER TO THE BATTERY SECTION FOR MORE
INFORMATION. CHARGE OR REPLACE BATTERY AS
NECESSARY.
2. STARTING CIRCUIT
WIRING FAULTY.2. REFER TO THE FEED CIRCUIT RESISTANCE TEST AND
THE FEED CIRCUIT TEST IN THIS SECTION. REPAIR AS
NECESSARY.
3. STARTER ASSEMBLY
FAULTY.3. IF ALL OTHER STARTING SYSTEM COMPONENTS AND
CIRCUITS CHECK OK, REPLACE STARTER ASSEMBLY.
4. ENGINE SEIZED. 4. REFER TO THE ENGINE SECTION, FOR DIAGNOSTIC AND
SERVICE PROCEDURES.
5. LOOSE
CONNECTION AT
BATTERY, PDC,
STARTER, OR ENGINE
GROUND.5. INSPECT FOR LOOSE CONNECTIONS.
6. FAULTY TEETH ON
RING GEAR.6. ROTATE FLYWHEEL 360É, AND INSPECT TEETH AND RING
GEAR REPLACED IF DAMAGED.
RGSTARTING8Fa-33
STARTING (Continued)
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Remove the starter relay from the PDC as
described in this group to perform the following tests:
(1) A relay in the de-energized position should
have continuity between terminals 87A and 30, and
no continuity between terminals 87 and 30. If OK, go
to Step 2. If not OK, replace the faulty relay.
(2) Resistance between terminals 85 and 86 (elec-
tromagnet) should be 75  5 ohms. If OK, go to Step
3. If not OK, replace the faulty relay.
(3) Connect a battery B+ lead to terminals 86 and
a ground lead to terminal 85 to energize the relay.
The relay should click. Also test for continuity
between terminals 30 and 87, and no continuity
between terminals 87A and 30. If OK, refer to Relay
Circuit Test procedure. If not OK, replace the faulty
relay.CAV FUNCTION
30 B (+)
85 P/N POSITION SW.SENSE
86 IGNITION SWITCH OUTPUT
87 STARTER RELAY OUTPUT
87A NO CONNECT
RELAY CIRCUIT TEST
(1) The relay common feed terminal cavity (30) is
connected to battery voltage and should be hot at all
times. If OK, go to Step 2. If not OK, repair the open
circuit to the PDC fuse as required.
(2) The relay normally closed terminal (87A) is
connected to terminal 30 in the de-energized position,
but is not used for this application. Go to Step 3.
(3) The relay normally open terminal (87) is con-
nected to the common feed terminal (30) in the ener-
gized position. This terminal supplies battery voltage
to the starter solenoid field coils. There should be
continuity between the cavity for relay terminal 87
and the starter solenoid terminal at all times. If OK,
go to Step 4. If not OK, repair the open circuit to the
starter solenoid as required.
(4) The coil battery terminal (86) is connected to
the electromagnet in the relay. It is energized when
the ignition switch is held in the Start position and
the clutch pedal is depressed (manual trans). Check
for battery voltage at the cavity for relay terminal 86
with the ignition switch in the Start position and the
clutch pedal is depressed (manual trans), and no
voltage when the ignition switch is released to the
On position. If OK, go to Step 5. If not OK, check for
an open or short circuit to the ignition switch and
repair, if required. If the circuit to the ignition switch
is OK, see the Ignition Switch Test procedure in this
group.
(5) The coil ground terminal (85) is connected to
the electromagnet in the relay. It is grounded
through the transmission range sensor only when the
gearshift selector lever is in the Park or Neutral
positions. Check for continuity to ground at the cav-
ity for relay terminal 85. If not OK with an auto-
matic transmission, check for an open or short circuit
to the transmission range sensor and repair. It is
grounded by the PCM if the conditions are right to
start the car. For automatic trans. cars the PCM
must see Park Neutral switch and near zero engine
rpm. For manual trans. cars the PCM only needs to
see near zero engine rpm. To diagnose the Park Neu-
tral switch of the trans range sensor refer to the
transaxle section for more information. Check for
continuity to ground while the ignition switch is in
the start position. If not OK and the vehicle has an
automatic trans. verify Park Neutral switch opera-
Starter Relay Pinout
Starter Relay Pinout
RGSTARTING8Fa-35
STARTING (Continued)
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tion. If that checks OK check for continuity between
PCM and the terminal 85. Repair open circuit as
required. If OK, the PCM may be defective.
SAFETY SWITCHES
For diagnostics of the Transmission Range Sensor,
refer to the Transaxle section for more information.
If equipped with Clutch Interlock/Upstop Switch,
refer to Diagnosis and Testing in the Clutch section.
IGNITION SWITCH
After testing starter solenoid and relay, test igni-
tion switch and wiring. Refer to the Ignition Section
or Wiring Diagrams for more information. Check all
wiring for opens or shorts, and all connectors for
being loose or corroded.
BATTERY
For battery diagnosis and testing, refer to the Bat-
tery section for procedures.
ALL RELATED WIRING AND CONNECTORS
Refer to Wiring Diagrams for more information.
DIAGNOSIS AND TESTING - FEED CIRCUIT
RESISTANCE TEST
Before proceeding with this operation, review Diag-
nostic Preparation and Starter Feed Circuit Tests.
The following operation will require a voltmeter,
accurate to 1/10 of a volt.
CAUTION: Ignition and Fuel systems must be dis-
abled to prevent engine start while performing the
following tests.
(1) To disable the Ignition and Fuel systems, dis-
connect the Automatic Shutdown Relay (ASD). The
ASD relay is located in the Power Distribution Cen-
ter (PDC). Refer to the PDC cover for proper relay
location.
(2) Gain access to battery terminals.
(3) With all wiring harnesses and components
properly connected, perform the following:
(a) Connect the negative lead of the voltmeter to
the battery negative post, and positive lead to the
battery negative cable clamp. Rotate and hold the
ignition switch in the START position. Observe the
voltmeter. If voltage is detected, correct poor con-
tact between cable clamp and post.
(b) Connect positive lead of the voltmeter to the
battery positive post, and negative lead to the bat-
tery positive cable clamp. Rotate and hold the igni-
tion switch key in the START position. Observe the
voltmeter. If voltage is detected, correct poor con-
tact between the cable clamp and post.(c) Connect negative lead of voltmeter to battery
negative terminal, and positive lead to engine
block near the battery cable attaching point.
Rotate and hold the ignition switch in the START
position. If voltage reads above 0.2 volt, correct
poor contact at ground cable attaching point. If
voltage reading is still above 0.2 volt after correct-
ing poor contacts, replace ground cable.
(4) Connect positive voltmeter lead to the starter
motor housing and the negative lead to the battery
negative terminal. Hold the ignition switch key in
the START position. If voltage reads above 0.2 volt,
correct poor starter to engine ground.
(a) Connect the positive voltmeter lead to the
battery positive terminal, and negative lead to bat-
tery cable terminal on starter solenoid. Rotate and
hold the ignition switch in the START position. If
voltage reads above 0.2 volt, correct poor contact at
battery cable to solenoid connection. If reading is
still above 0.2 volt after correcting poor contacts,
replace battery positive cable.
(b) If resistance tests do not detect feed circuit
failures, replace the starter motor.
DIAGNOSIS AND TESTING - FEED CIRCUIT
TEST
NOTE: The following results are based upon the
vehicle being at room temperature.
The following procedure will require a suitable
volt-ampere tester (Fig. 3).
CAUTION: Before performing any starter tests, the
ignition and fuel systems must be disabled.
(1) Check battery before performing this test. Bat-
tery must be fully charged.
(2) Connect a volt-ampere tester to the battery ter-
minals. Refer to the operating instructions provided
with the tester being used.
Fig. 3 Volt Ampere Tester
8Fa - 36 STARTINGRG
STARTING (Continued)
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CONDITION POSSIBLE CAUSES CORRECTION
Key fob, Outside Handle or
overhead console switches
do not power operate
liftgateBlown Fuse Check fuse and replace
Battery voltage low Charge or replace battery in key fob or
vehicle
Failure of latch assembly Check for foreign matter preventing the
operation of latch assembly
Check wire connection
Pawl and/or ratchet switch inoperative
Replace latch if necessary
Wiring problems (system or vehicle) Troubleshoot using electrical schematics.
Refer to wiring diagrams
Failure of Body Control Module
(BCM)Check electrical connections
Refer to the Body electrical troubleshooting
guide for additional checks
Replace BCM if necessary
Failure of key fob Reprogram key fob
Replace key fob if necessary
Failure of Power Liftgate Module Disconnect then reconnect battery to reset
module, function liftgate, if no function
exists check for loose wire connections,
see Body Diagnostic Manual for detailed
procedures
Failure of liftgate motor assembly Check for foreign matter preventing the
operation of gear motor assembly
Check wire connections
Motor clutch does not engage, replace
assembly
Full open switch inoperative, replace
switch, if necessary
Troubleshoot using Body Diagnostic
Manual Replace motor, if necessary
Liftgate does not stay open Failure of liftgate prop rods Replace prop rods, if necessary
Check for broken attachments
High inside/outside opening
effortFailure of liftgate prop rods Replace prop rods, if necessary
Check for broken attachments
Gear motor did not disengage Troubleshoot using Body Diagnostic
Manual Replace components, if necessary
Binding or sticking of components Establish location of binding and replace
necessary components
RSPOWER LIFTGATE SYSTEM8N-7
POWER LIFTGATE SYSTEM (Continued)
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CONDITION POSSIBLE CAUSES CORRECTION
Striker damaged
Replace striker if necessary
Cables worn and stretched Replace cables as necessary
Binding or sticking of components Establish location of binding and replace
necessary components
Key fob, B-pillar or
overhead console switch
does not power operate
doorBlown Fuse Check fuse and replace
Battery voltage low Charge or replace battery
Failure of latch assembly Check for foreign matter preventing the
operation of latch assembly
Check wire connection
Pawl and/or ratchet switch inoperative
Replace latch if necessary
Wiring problems (system or vehicle) Troubleshoot using electrical schematics.
Refer to wiring diagrams
Failure of body control module Check electrical connections
Refer to the body diagnostic manual for
additional checks
Replace BCM if necessary
Failure of key fob Replace key fob battery
Replace key fob if necessary
Failure of sliding door control module Disconnect then reconnect battery to reset
module, function door, if no function exists
check for loose wire connections, see Body
Diagnostic Manual for detailed procedures
Failure of door motor assembly Check for foreign matter preventing the
operation of gear motor assembly
Check wire connections
Gear motor clutch does not engage,
replace assembly
Full open switch inoperative, replace hold
open latch assembly
Replace motor assembly. if necessary
Door does not stay open Failure of hold open latch assembly Check wire/cable connections
Replace hold open latch, if necessary
Failure of hold open latch striker Replace hold open latch striker, if
necessary
High inside/outside opening
effortFailure of latch assembly Check wire connections and for blown fuse
Check cable connections
RSPOWER SLIDING DOOR SYSTEM8N-25
POWER SLIDING DOOR SYSTEM (Continued)
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(5) Partially close the door and pull the latch
assembly out of the side door inner panel.
(6) Disconnect all electrical connectors leading to
the latch assembly.
(7) Disconnect the inside and outside handle cables
from the latch assembly. Refer to the Body Section of
the service manual for the procedure.
(8) Disconnect the hold open latch cable from the
latch assembly. Refer to the Body Section of the ser-
vice manual for the procedure.
(9) Disconnect lock actuator link rod from the
latch assembly.
(10) Remove the latch assembly from the vehicle.
INSTALLATION
(1) Position the latch assembly in the vehicle. Be
certain all latch mounted components are installed
on the replacement latch assembly. If not, transfer
components from the old latch to the new latch
assembly.
(2) Connect the lock actuator link rod on the latch
assembly.
(3) Connect the hold open latch cable on the latch
assembly. Refer to the procedure in this section for
detailed instructions.
(4) Connect the inside and outside handle cables
on the latch assembly. Refer to the procedure in the
Body section for detailed instructions.
(5) Connect all electrical connectors leading to the
latch assembly.
(6) With assistance from another person, position
the side door and install the door latch retaining
bolts. Torque to 10 - 12 N´m (100 in. lbs.).
(7) Install the weathershield if necessary. Refer to
the procedure in the Body section for detailed
instructions.
(8) Install the appropriate side door trim panel.
Refer to the procedure in the Body section for
detailed instructions.
(9) Connect the negative battery cable.
SLIDING DOOR MOTOR
DESCRIPTION
Vehicles equipped with a power sliding door utilize
a door motor assembly. The door motor is located in
the center of the side door (Fig. 7) and is comprised
of three parts. The three parts of the door motor
assembly are the motor, gear reduction and clutch
assembly. The door motor assembly provides the
power and torque to move the sliding door from the
open/closed position to full closed/open position, after
the power latching mechanism has released.
Special wellnuts and screws are used in the side
door inner panel to retain the door motor to the doorpanel. Refer to Standard Procedures in this section
for additional wellnut information.
The door motor is replaced as a complete assembly,
which includes the DC motor, gear reduction and
clutch assemblies. Consult your Mopar parts catalog
for specific part numbers.
OPERATION
With the push of a Power Side Door (PSD) com-
mand switch, the PSD control module will signal the
latch assembly to release the door from its primary
locked position. The drive motor will then take over
to provide the power to open the door to its full open
or closed position. The gear reduction portion of the
motor assembly reduces the speed of the motor from
5800 to 260 rpm and also increases the torque to the
lower drive unit. The clutch portion of the motor
assembly engages the motor to drive the door under
power and disengages it so the door can be moved
easily under manual operation.
REMOVAL
(1) Disconnect and isolate the negative battery
cable.
Fig. 7 Side Door Components
1 - Sliding Door Control Module
2 - Module Retaining Screw
3 - Module Electrical Connectors
4 - Door Motor Assembly
5 - Flex Drive Assembly
6 - Door Motor Retaining Fasteners
7 - Door Motor Electrical Connector
RSPOWER SLIDING DOOR SYSTEM8N-29
LATCH (Continued)
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SLIDING DOOR MODULE
DESCRIPTION
Vehicles equipped with a power sliding door utilize
a sliding door control module. The sliding door con-
trol module is located behind the sliding door trim
panel in the center of the door, just above the sliding
door motor (Fig. 22). This module controls the opera-
tion of the door through the Programmable Commu-
nication Interface (PCI) J1850 data bus circuit and
the Body Control Module. The sliding door control
module contains software technology which enables it
to detect resistance to door travel and to reverse door
travel in order to avoid damage to the door or to
avoid possible personal injury if the obstruction is a
person. This feature functions in both the opening
and closing cycles. If the power sliding door system
develops any problems the control module will store
and recall Diagnostic Trouble Codes (DTC). The use
of a diagnostic scan tool, such as the DRB IIItis
required to read and troubleshoot these trouble
codes. The sliding door control module can be
reflashed if necessary. Refer to the latest Technical
Service Bulletin (TSB) Information for any updates.
The power door control module is a replaceable
component and cannot be repaired, if found to be
faulty it must be replaced. Consult your MoparŸ
parts catalog for a specific part number.OPERATION
The power sliding door control module serves as
the main computer for the power sliding side door
system. All power door functions are processed
through the power door control module and/or the
vehicles body control module (BCM). At the start of a
power open command, a signal is sent to the BCM
and then to the power door control module via the
J1850 data bus circuit. This signal, generated by any
of the power door command switches, tells the power
door control module to activate a power latch release,
engage the clutch assembly and drive the door into
the full open position. If an obstacle is felt during
this power open cycle, the module will reverse direc-
tion and close the door. This process is also enabled
during a power close cycle. This process will repeat
three times, and if a fourth obstacle is detected, the
door will go into full manual mode. Once the full
open position is obtained, a hold open latch assembly
mounted full open switch tells the control module
that the door has reached the full open position. If
the power sliding door system develops any problems
the control module will store and recall Diagnostic
Trouble Codes (DTC). The use of a diagnostic scan
tool, such as the DRB IIItis required to read and
troubleshoot these trouble codes.
Fig. 21 Flex Drive Cable
1 - Door Motor
2 - Flex Drive Collar
3 - Flex Drive Inner Shaft
Fig. 22 Side Door Components
1 - Sliding Door Control Module
2 - Module Retaining Screw
3 - Module Electrical Connectors
4 - Door Motor Assembly
5 - Flex Drive Assembly
6 - Door Motor Retaining Fasteners
7 - Door Motor Electrical Connector
RSPOWER SLIDING DOOR SYSTEM8N-37
FLEX DRIVE (Continued)
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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..........................5
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. The speed
control can be disengaged 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
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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. Interactive speed
control avoids unnecessary shifting for smoother, qui-
eter 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 TCM identifies the powertrain loading condi-
tions and selects the proper gear to maintain the cur-
rent vehicle speed. Under moderate loading
conditions the transaxle will stay in 3rd gear until
the top of the grade is reached or the powertrain
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)
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