2004 CHRYSLER VOYAGER tires

ABS SECONDARY HYDRAULIC CIRCUIT AND
SOLENOID VALVE FUNCTION (ABS WITHOUT
TRACTION CONTROL)
The hydraulic diagram (Fig. 8) shows the vehicle in
the ABS braking mode. The diagram shows one
wheel is slipping because the driver is attempting to
stop the vehicle at a faster rate than is allowed by
the surface on which the tires are riding.
²The normally open and normally closed valves
modulate (build/decay) the brake hydraulic pressure
as required.²The pump/motor is switched on so that the
brake fluid from the low pressure accumulators is
returned to the master cylinder circuits.
²The brake fluid will then be routed to either the
master cylinder or the wheel brake depending on the
position of the normally open valve.
²In the secondary circuit, 1.2 cc brake fluid is
taken in by the lip seal saver to protect the lip seals
on the master cylinder piston.
Fig. 8 ABS Without Traction Control - Secondary Hydraulic Circuit
1 - OUTLET VALVE
2 - PUMP PISTON
3 - LOW PRESSURE ACCUMULATOR PRESSURE
4 - TO RIGHT FRONT WHEEL
5 - FROM MASTER CYLINDER6 - MASTER CYLINDER PRESSURE
7 - CONTROLLED WHEEL PRESSURE
8 - PUMP INTERSTAGE PRESSURE
9 - LIP SEAL SAVER (SECONDARY CIRCUIT ONLY)
RSBRAKES - ABS5-85
HYDRAULIC/MECHANICAL (Continued)

ABS BRAKING HYDRAULIC CIRCUIT, SOLENOID
VALVE, AND SHUTTLE VALVE FUNCTION (ABS
WITH TRACTION CONTROL)
The hydraulic diagram (Fig. 10) shows the vehicle
in the ABS braking mode. The diagram shows one
wheel is slipping because the driver is attempting to
stop the vehicle at a faster rate than is allowed by
the surface on which the tires are riding.
²The hydraulic shuttle valve closes upon brake
application so that the pump/motor cannot siphon
brake fluid from the master cylinder.²The normally open and normally closed valves
modulate (build/decay) the brake hydraulic pressure
as required.
²The pump/motor is switched on so that the
brake fluid from the low pressure accumulators is
returned to the master cylinder circuits.
²The brake fluid is routed to either the master
cylinder or the wheel brake depending on the posi-
tion of the normally open valve.
Fig. 10 ABS With Traction Control - ABS Braking Hydraulic Circuit
1 - OUTLET VALVE
2 - PUMP PISTON
3 - PUMP MOTOR (ON)
4 - SUCTION VALVE
5 - LOW PRESSURE ACCUMULATOR
6 - NORMALLY CLOSED VALVE (MODULATING)
7 - TO RIGHT FRONT WHEEL
8 - NORMALLY OPEN VALVE (MODULATING)9 - NORMALLY OPEN ASR VALVE (OFF)
10 - FROM MASTER CYLINDER
11 - HYDRAULIC SHUTTLE VALVE
12 - MASTER CYLINDER PRESSURE
13 - CONTROLLED WHEEL PRESSURE
14 - LOW PRESSURE ACCUMULATOR PRESSURE
15 - PUMP INTERSTAGE PRESSURE
16 - NOISE DAMPER CHAMBER
RSBRAKES - ABS5-87
HYDRAULIC/MECHANICAL (Continued)

OPERATION - SENSOR RETURN - PCM INPUT
The sensor return circuit provides a low electrical
noise ground reference for all of the systems sensors.
The sensor return circuit connects to internal ground
circuits within the Powertrain Control Module
(PCM).
OPERATION - DATA BUS COMMUNICATION
RECEIVE - PCM INPUT
The PCM uses the SCI communication bus to pre-
form engine diagnostics and flash operations. The
transmission side of the PCM uses the SCI commu-
nication bus to flash new software. However, diagnos-
tics is performed via the vehicles J1850 bus for the
transmission side of the PCM.
OPERATION - IGNITION SENSE - PCM INPUT
The ignition sense input informs the Powertrain
Control Module (PCM) that the ignition switch is in
the crank or run position.
OPERATION - PCM GROUND
Ground is provided through multiple pins of the
PCM connector. Depending on the vehicle there may
be as many as two different ground pins. There are
power grounds and sensor grounds.
The power grounds are used to control the ground
side relays, solenoids, ignition coil or injectors. The
signal ground is used for any input that uses sensor
return for ground, and the ground side of any inter-
nal processing component.
The PCM case is shielded to prevent RFI and EMI.
The PCM case is grounded and must be firmly
attached to a good, clean body ground.
Internally all grounds are connected together, how-
ever there is noise suppression on the sensor ground.
For EMI and RFI protection the housing and cover
are also grounded separately from the ground pins.
OPERATION
OPERATION - 8-VOLT SUPPLY - PCM OUTPUT
- SBEC CONTROLLER
The PCM supplies 8 volts to the crankshaft posi-
tion sensor, camshaft position sensor.
OPERATION - 5 VOLT SUPPLY - PCM OUTPUT
The PCM supplies 5 volts to the following sensors:
²A/C pressure transducer
²Ambient Temperature sensor
²Battery temperature
²Camshaft Position Sensor (NGC)
²Crankshaft Position Sensor (NGC)
²Electronic Throttle Control (1.6L)²Engine coolant temperature sensor
²Inlet Air Temperature Sensor
²Knock sensor
²Linear EGR solenoid (if equipped)
²Manifold absolute pressure sensor
²Oil Pressure Switch
²Pedal Position Sensor (1.6L)
²Throttle position sensor
²Vehicle Speed Sensor
STANDARD PROCEDURE
STANDARD PROCEDURE - OBTAINING
DIAGNOSTIC TROUBLE CODES
BULB CHECK
Key on: Bulb illuminated until vehicle starts, as
long as all once per trip (readiness) monitors com-
pleted. If monitors havenotbeen completed, then:
Key on: bulb check for about 5 to 8 seconds, lamp
then flashes if once per trip (readiness) monitors
havenotbeen completed until vehicle is started,
then MIL is extinguished.
OBTAINING DTC'S USING DRB SCAN TOOL
(1) Connect the DRB scan tool to the data link
(diagnostic) connector. This connector is located in
the passenger compartment; at the lower edge of
instrument panel; near the steering column.
(2) Turn the ignition switch on and access the
ªRead Faultº screen.
(3) Record all the DTC's and ªfreeze frameº infor-
mation shown on the DRB scan tool.
(4) To erase DTC's, use the ªErase Trouble Codeº
data screen on the DRB scan tool.Do not erase any
DTC's until problems have been investigated
and repairs have been performed.
STANDARD PROCEDURE - PINION FACTOR
SETTING
NOTE: This procedure must be performed if the
PCM/TCM has been replaced with a NEW or
replacement unit. Failure to perform this procedure
will result in an inoperative or improperly calibrated
speedometer.
The vehicle speed readings for the speedometer are
taken from the output speed sensor. The PCM/TCM
must be calibrated to the different combinations of
equipment (final drive and tires) available. Pinion
Factor allows the technician to set the Powertrain/
Transmission Control Module initial setting so that
the speedometer readings will be correct. To properly
RSELECTRONIC CONTROL MODULES8E-15
POWERTRAIN CONTROL MODULE (Continued)

STANDARD PROCEDURE
STANDARD PROCEDURE - PINION FACTOR
SETTING
NOTE: This procedure must be performed if the
PCM/TCM has been replaced with a NEW or
replacement unit. Failure to perform this procedure
will result in an inoperative or improperly calibrated
speedometer.
The vehicle speed readings for the speedometer are
taken from the output speed sensor. The PCM/TCM
must be calibrated to the different combinations of
equipment (final drive and tires) available. Pinion
Factor allows the technician to set the Powertrain/
Transmission Control Module initial setting so that
the speedometer readings will be correct. To properly
read and/or reset the Pinion Factor, it is necessary to
use a DRBIIItscan tool.
(1) Plug the DRBIIItscan tool into the diagnostic
connector located under the instrument panel.
(2) Select the Transmission menu.
(3) Select the Miscellaneous menu.
(4) Select Pinion Factor. Then follow the instruc-
tions on the DRBIIItscan tool screen.
STANDARD PROCEDURE - QUICK LEARN
PROCEDURE
The quick learn procedure requires the use of the
DRBIIItscan tool. This program allows the PCM/
TCM to recalibrate itself. This will provide the best
possible transaxle operation.
NOTE: The quick learn procedure should be per-
formed if any of the following procedures are per-
formed:
²Transaxle Assembly Replacement
²Powertrain/Transmission Control Module
Replacement
²Solenoid/Pressure Switch Assembly Replacement
²Clutch Plate and/or Seal Replacement
²Valve Body Replacement or Recondition
To perform the Quick Learn Procedure, the follow-
ing conditions must be met:
²The brakes must be applied
²The engine speed must be above 500 rpm
²The throttle angle (TPS) must be less than 3
degrees
²The shift lever position must stay until
prompted to shift to overdrive
²The shift lever position must stay in overdrive
after the Shift to Overdrive prompt until the
DRBIIItindicates the procedure is complete²The calculated oil temperature must be above
60É and below 200É
(1) Plug the DRBIIItscan tool into the diagnostic
connector. The connector is located under the instru-
ment panel.
(2) Go to the Transmission screen.
(3) Go to the Miscellaneous screen.
(4) Select Quick Learn Procedure. Follow the
instructions of the DRBIIItto perform the Quick
Learn Procedure.
REMOVAL
NOTE: If transmission control module is being
replaced with a new or replacement unit, the Pinion
Factor and Quick Learn procedures must be per-
formed. (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/TRANSMISSION CONTROL
MODULE - STANDARD PROCEDURE) (Refer to 8 -
ELECTRICAL/ELECTRONIC CONTROL MODULES/
TRANSMISSION CONTROL MODULE - STANDARD
PROCEDURE)
(1) Disconnect battery negative cable.
(2) Raise vehicle on hoist.
(3) Remove left front tire/wheel assembly.
(4) Pull back splash shield to gain access to TCM
location.
(5) Disconnect TCM 60-way connector (Fig. 18).
(6) Remove three (3) TCM-to-rail screws and
remove TCM from vehicle (Fig. 19).
Fig. 18 Transmission Control Module 60-way
Connector
1 - TRANSMISSION CONTROL MODULE (TCM)
2 - 60-WAY CONNECTOR
RSELECTRONIC CONTROL MODULES8E-23
TRANSMISSION CONTROL MODULE (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
ERRATIC POINTER
MOVEMENT.1. ERRATIC MESSAGE
FROM ANOTHER
MODULE.1.A. CHECK THE BCM USING A DRB IIITSCAN TOOL IF
OK, GO TO STEP 1.B. IF NOT OK, REFER TO THE
PROPER BODY DIAGNOSTIC PROCEDURES MANUAL
TO REPAIR THE BCM.
1.B. CHECK THE PCM USING A DRB IIITSCAN TOOL. IF
OK, GO TO STEP 1.C. IF NOT OK, REFER TO THE
PROPER POWERTRAIN DIAGNOSTIC PROCEDURES
MANUAL TO REPAIR THE PCM.
1.C. CHECK THE SPEED SIGNAL INPUT INTO THE PCM.
THE SPEED SIGNAL ORIGINATES FROM THE TCM FOR
VEHICLES WITH THE 4 SPEED ELECTRONIC
TRANSMISSIONS. CHECK CONTINUITY FROM TCM TO
PCM. IF OK, USE A DRB IIITSCAN TOOL TO CHECK
TCM. REFER TO THE PROPER TRANSMISSION
DIAGNOSTIC PROCEDURES MANUAL TO REPAIR THE
TCM. IF NOT OK, REPAIR WIRING.
2. INTERNAL CLUSTER
FAILURE.2.A. PERFORM CLUSTER SELF-DIAGNOSTIC TEST AND
CHECK FOR FAULT CODES.
²IF THE POINTER MOVES DURING TEST BUT STILL
APPEARS ERRATIC, THEN GO TO STEP 2.B.
2.B. REPLACE CLUSTER ASSEMBLY.
SPEEDOMETER
INACCURATE.1. SPEEDOMETER OUT
OF CALIBRATION.1. PERFORM CLUSTER SELF-DIAGNOSTIC TEST.
²IF SPEEDOMETER IS ACCURATE TO THE
CALIBRATION POINTS THEN LOOK FOR ANOTHER
POSSIBLE CAUSE OF INACCURACY.
²IF SPEEDOMETER IS NOT ACCURATE TO THE
CALIBRATION POINTS, REPLACE CLUSTER ASSEMBLY.
2. WRONG
SPEEDOMETER PINION
FOR TIRE SIZE.2.A. IF VEHICLE HAS A 4 SPEED ELECTRONIC
TRANSMISSION GO TO STEP 2.C. OTHERWISE GO TO
STEP 2.B.
2.B. CHECK IF CORRECT SPEEDOMETER PINION IS
BEING USED WITH TIRES ON VEHICLE. REFER TO
TRANSMISSION FOR DIAGNOSIS AND TESTING.
²IF THE INCORRECT PINION IS IN TRANSMISSION
THEN REPLACE WITH CORRECT PINION.
²IF THE CORRECT PINION IS IN THE TRANSMISSION,
CHECK TIRE SIZE.
2.C. USE A DRB IIITSCAN TOOL TO CHECK THE TCM
TO SEE IF THE CORRECT TIRE SIZE HAS BEEN
PROGRAMMED INTO THE TCM.
²IF THE INCORRECT TIRE SIZE WAS SELECTED,
SELECT THE PROPER TIRE SIZE.
²IF THE CORRECT TIRE SIZE WAS SELECTED, CHECK
SPEED SENSOR.
3. BAD SPEED SENSOR. 3. REFER TO TRANSMISSION, SPEED SENSOR,
DIAGNOSIS AND TESTING.
RSINSTRUMENT CLUSTER8J-5
INSTRUMENT CLUSTER (Continued)

PROGRAMMABLE FEATURES
NOTE: Tire pressure monitoring (TPM) system infor-
mation is not covered in this section of the service
manual. Refer to the tires/wheels section of this
manual for detailed tire pressure monitoring system
information.
²LANGUAGE?- The options include English,
Francaise, Deutsch, Italiana, or Espanol. The default
is English. All EVIC display nomenclature, including
the trip computer functions, warning messages and
the programmable features appear in the selected
language.
²DISPLAY U.S. OR METRIC?- The options
include U.S. and M. The default is U.S. This feature
toggles the trip computer temperature, fuel economy
and odometer display readings between U.S. and
metric units of measure. It also changes the odome-
ter display in the instrument cluster.
²SERVICE INTV. =- The options include from
1000 to 12000 kilometers in 1000 kilometer incre-
ments (2000 to 7500 miles in 500 mile increments).
The default is 12000 kilometers (7500 miles). The
selected distance becomes the interval at which the
Perform Service warning message will be displayed
by the EVIC. If a new distance is selected, a second
programmable feature appears,RESET SERVICE
DISTANCE?- The options include No and Yes. The
default is Yes. When Yes is selected, the accumulated
distance since the last previous Perform Service
warning message will be reset to zero because the
service interval has been changed. When No is
selected, the distance until the next Perform Service
warning message is reduced by the accumulated dis-
tance since the last previous message.
²USE FACTORY SETTINGS?- The options
include Yes and No. The default is Yes. When yes is
selected all the programmable features will return to
there defaults and the rest of the programmable fea-
tures will not be displayed. If No is selected the rest
of the programmable features will be displayed at
there default values. This feature will automatically
return to the Yes default under two conditions. First,
if no programmable features are changed from there
defaults. Second, if all the programmable features
equal there defaults.
²AUTO DOOR LOCKS?- The options include
Yes and No. The default is Yes. When Yes is selected,
all doors and the liftgate lock automatically when
vehicle speed reaches 25 kilometers-per-hour (15
miles-per-hour). If YES is selected, a second program-
mable feature appears,AUTO UNLOCK ON EXIT?
- The options again include Yes and No. The default
is No. When Yes is selected, following each Auto Door
Lock event all doors and the liftgate will automati-
cally unlock when the driver door is opened, if thevehicle is stopped and the transmission gear selector
is in Park or Neutral. The Auto Door Unlock event
will only occur once following each Auto Door Lock
event.
²REMOTE UNLOCK- The options include
Driver Door 1st and All Doors. The default is Driver
Door 1st. When Diver Door 1st is selected, only the
driver door unlocks when the Unlock button of the
Remote Keyless Entry (RKE) transmitter is
depressed once. The Unlock button of the RKE trans-
mitter must be depressed twice to unlock all doors.
When All Doors is selected, all doors unlock when the
Unlock button of the RKE transmitter is depressed
once.
²REMOTE LINKED TO MEMORY?- This pro-
grammable feature only applies to vehicles equipped
with the optional memory / heated system. The
options include Yes and No. The default is No. When
Yes is selected, the memory system will recall the
Driver 1 or Driver 2 memory settings assigned to the
RKE transmitter being used to unlock the vehicle.
When No is selected, the memory system will only
recall memory settings when the Driver 1 or Driver 2
push buttons of the memory switch on the driver side
front door trim panel are depressed.
²SOUND HORN ON LOCK?- The options
include Yes and No. The default is No. When Yes is
selected, a short horn chirp will provide an audible
confirmation when the RKE receiver recognizes a
valid Lock signal from an RKE transmitter. When No
is selected, no horn chirp will occur with the RKE
Lock event. This feature may be selected indepen-
dent of theFLASH LIGHTS WITH LOCKS?pro-
grammable feature.
²FLASH LIGHTS WITH LOCKS?- The options
include Yes and No. The default is Yes. When Yes is
selected, a single flash of the hazard warning lamps
will provide an optical confirmation when the RKE
receiver recognizes a valid Lock signal from an RKE
transmitter, and two flashes of the same lamps will
occur when the RKE receiver recognizes a valid
Unlock signal from an RKE transmitter. When No is
selected, no lamp flash will occur with the RKE Lock
or Unlock event. This feature may be selected inde-
pendent of theSOUND HORN ON LOCK?pro-
grammable feature.
²HEADLAMP DELAY =- The options include
Off, 30 Sec, 60 Sec, and 90 Sec. The default is 90 Sec.
When a time interval is selected, the headlamps will
remain on for that length of time when the head-
lamps are turned off after the ignition is turned off,
or if the Auto mode is selected on vehicles with the
Auto Headlamps option. When Off is selected, the
headlamp delay feature is disabled.
²HEADLAMPS ON WITH WIPERS?- This pro-
grammable feature only applies to vehicles equipped
8M - 8 MESSAGE SYSTEMSRS
ELECTRONIC VEHICLE INFO CENTER (Continued)

with the optional Auto Headlamps. The options
include Yes and No. The default is No. When Yes is
selected, the headlamps will turn on automatically
when the windshield wipers are turned on. The head-
lamps will turn off when the wipers are turned off,
as long as the headlamp switch is in the Auto or Off
positions. When No is selected, the headlamps will
only turn on if manually selected or if the Auto mode
is selected and the outside ambient light levels dic-
tate that they should be on.
²RETRAIN TIRE SENSORS?- This program-
mable feature only applies to vehicles equipped with
the optional Tire Pressure Monitoring System. The
options include Yes and No. The default is No. When
Yes is selected, and the menu button is depressed the
EVIC will enter the training mode, starting with the
left front tire.
²POWER ACCESSORY DELAY?- The options
include Yes and No. The default is Yes. When No is
selected, the accessory powered components will turn
off automatically when the ignition key is turned off.
When Yes is selected, the accessory powered compo-
nents will remain on for 45 seconds when the igni-
tion key is turned off.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove overhead console. Refer to Overhead
Console Removal and Installation in this section(Re-
fer to 8 - ELECTRICAL/OVERHEAD CONSOLE -
REMOVAL).
(3) Remove the ten screws holding the EVIC mod-
ule in the overhead console.
(4) Remove EVIC module from console assembly.
NOTE: If the EVIC module is being replaced, the tire
pressure monitoring system (if equipped) must be
retrained. Refer to the Tires/Wheels section of this
manual for detailed instructions.
INSTALLATION
(1) Position the EVIC module in the overhead con-
sole.
(2) Install the ten screws holding the EVIC module
in the overhead console.
(3) Install the overhead console (Refer to 8 -
ELECTRICAL/OVERHEAD CONSOLE - INSTALLA-
TION).
(4) Connect the battery negative cable.
NOTE: If the EVIC module is being replaced, the tire
pressure monitoring system (if equipped) must be
retrained. Refer to the Tires/Wheels section of this
manual for detailed instructions.NOTE: If a new EVIC module has been installed, the
compass will have to be calibrated and the variance
set. Refer to compass variation adjustment and
compass calibration in standard procedures.
COMPASS/MINI-TRIP
COMPUTER
DESCRIPTION
The Compass Mini-Trip Computer (CMTC) and
Compass Temperature (CT) computer are modules
located in the overhead console. Vehicles are
equipped with either the CMTC or the CT computers
not both. The CMTC is different in the fact that it is
equipped with the mini-trip feature. The CMTC, CT
consists of a electronic control module with a vacuum
fluorescent display (VFD) and function switches. The
CMTC, CT consists of a electronic module that dis-
plays compass, trip computer (CMTC only), and tem-
perature features. Actuating the STEP push button
(CMTC only) will cause the CMTC to change mode of
operation when ignition is ON. Actuating the STEP
push button (CMTC only) will cause the CMTC to
change mode of operation when ignition is ON.
Example:
²Average miles per gallon (ECO)
²Distance to empty (DTE)
²Instant miles per gallon (ECO)
²Trip odometer (ODO)
²Elapsed time (ET)
²Off
Actuating the C/T push button will cause the
CMTC, CT to change to Compass/Temperature dis-
play.
OPERATION
The Compass Mini-Trip Computer (CMTC), Com-
pass Temperature (CT) module in the overhead con-
sole has buttons used to select various functions. The
CMTC, CT selector buttons will not operate until the
ignition is in the RUN position.
When the ignition switch is first turned to the
RUN position the CMTC, CT display;
²Blanks momentarily
²All segments of the VFD will light for one sec-
ond
²Blanks momentarily
²Returns to the last mode setting selected before
the ignition was last switched OFF.
RSMESSAGE SYSTEMS8M-9
ELECTRONIC VEHICLE INFO CENTER (Continued)

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 the
throttle 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 (on SBEC vehicles) (PCM on NGC vehi-
cles) identifies the powertrain loading conditions and
selects the proper gear to maintain the current vehi-
cle 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.
8P - 2 SPEED CONTROLRS
SPEED CONTROL (Continued)