The primary functions of the (CAB) are:
(1) Detect wheel locking or wheel slipping tenden-
cies by monitoring the speed of all four wheels of the
vehicle.
(2) Illuminate the TRAC lamp in the message cen-
ter on the instrument panel when a traction control
event is occurring.
(3) Control fluid modulation to the wheel brakes
while the system is in an ABS mode or the traction
control system is activated.
(4) Monitor the system for proper operation.
(5) Provide communication to the DRB Scan Tool
while in diagnostic mode.
(6) Store diagnostic information.
(7)The CAB continuously communicates with
the body controller by sending out a message to
the body controller on the CCD Bus. This mes-
sage is used for illumination of the yellow
antilock warning lamp. This is used if the ABS
controller communication is lost in the hard
wire between the body controller and the yel-
low antilock warning lamp. If the body control-
ler does not receive this message from the CAB,
the body controller will illuminate the antilock
yellow warning lamp.
The CAB continuously monitors the speed of each
wheel through the signals generated by the wheel
speed sensors to determine if any wheel is beginning
to lock. When a wheel locking tendency is detected,
the CAB commands the CAB command coils to actu-
ate. The CAB command coils then open and close the
valves in the HCU which modulate brake fluid pres-
sure in some or all of the hydraulic circuits. The CAB
continues to control pressure in individual hydraulic
circuits until a locking tendency is no longer present.
The ABS system is constantly monitored by the
CAB for proper operation. If the CAB detects a fault,
it will turn on the Amber ABS Warning Lamp anddisable the ABS braking system. The normal base
braking system will remain operational.
The CAB contains a self-diagnostic program which
will turn on the Amber ABS Warning Lamp when a
ABS system fault is detected. Faults are then stored
in a diagnostic program memory. There are multiple
fault messages which may be stored in the CAB and
displayed through the DRB Scan Tool. These fault
messages will remain in the CAB memory even after
the ignition has been turned off. The fault messages
can be read and or cleared from the CAB memory by
a technician using the DRB Scan Tool. The fault
occurrence and the fault code will also be automati-
cally cleared from the CAB memory after the identi-
cal fault has not been seen during the next 3500
miles of vehicle operation. Mileage though of the last
fault occurrence will not be automatically cleared.CONTROLLER ANTILOCK BRAKE INPUTS
²Four wheel speed sensors.
²Stop lamp switch.
²Ignition switch.
²System relay voltage.
²Ground.
²Traction Control Switch (If Equipped).
²Diagnostics Communications (CCD)
CONTROLLER ANTILOCK BRAKE OUTPUTS
²C2D Communication To Body Controller And
Instrument Cluster
²ABS warning lamp actuation.
²Traction Control Light (If Equipped).
²Diagnostic communication. (CCD)
ABS WARNING LAMP (YELLOW)
The ABS system uses a yellow colored ABS Warn-
ing Lamp. The ABS warning lamp is located on the
right side of the message center located at the top of
the instrument panel. The purpose of the warning
lamp is discussed in detail below.
The ABS warning lamp will turn on when the CAB
detects a condition which results in a shutdown of
ABS function or when the body controller does not
receive C2D messages from the CAB. When the igni-
tion key is turned to the on position, the ABS Warn-
ing Lamp is on until the CAB completes its self tests
and turns the lamp off (approximately 4 seconds
after the ignition switch is turned on). Under most
conditions, when the ABS warning lamp is on, only
the ABS function of the brake system is affected. The
standard brake system and the ability to stop the car
will not be affected when only the ABS warning lamp
is on.
The ABS warning lamp is controlled by the CAB
and the body controller through a diode located in
the wiring harness junction block. The junction block
is located under the instrument panel to the left of
Fig. 10 Controller Antilock Brake (CAB)
NSBRAKES 5 - 91
DESCRIPTION AND OPERATION (Continued)
DOOR LOCK INHIBIT FEATURE
The BCM cancels out the door lock switch actua-
tion, when the key is in the Ignition Switch and a
door is open. After the key is removed from the Igni-
tion Switch, or the doors are closed, the power door
locks will operate normally.
SLIDING DOOR LOCK MEMORY FEATURE
The door locks on the sliding door(s) can be actu-
ated when the door(s) are closed. If the sliding
door(s) are open when the door locks are actuated,
the BCM will hold the lock command in memory
until the door(s) is closed. When the door is closed
and the door jamb terminals make contact, signaling
the BCM to lock the sliding door(s) automatically.
Actuating the door lock switch to the unlock position
before the sliding door(s) are closed will cancel the
lock request.
DIAGNOSIS AND TESTING
AUTOMATIC DOOR LOCK SYSTEM TEST
When using a scan tool (DRB) for testing the auto-
matic door lock system, refer to the Body Diagnostic
Procedures Manual. Refer to Group 8W, Wiring Dia-
grams for circuit information and component loca-
tions.
DOOR LOCK MOTOR
Verify battery condition before testing door lock
motor(s), refer to Group 8A, Battery for proper diag-
nosis procedures.
To determine which motor is faulty, check each
individual door for electrical lock and unlock or dis-
connect the motor connectors one at a time, while
operating the door lock switch. In the event that
none of the motors work, the problem may be caused
by a shorted motor, a relay or a bad switch. Discon-
necting the defective motor will allow the others to
work.
To test an individual door lock motor, disconnect
the electrical connector from the motor. To lock the
door, connect a 12 volt power source to the positive
pin of the lock motor and a ground wire to the other
pin (Fig. 1), (Fig. 2), (Fig. 3) and refer to Group 8W,
Wiring Diagrams for pin locations. To unlock the door
reverse the wire connections at the motor pin termi-
nals. If these results are NOT obtained, replace the
motor.
DOOR LOCK SWITCH TEST
(1) Remove door lock switch bezel assembly from
door. Refer to Group 23, Body for removal proce-
dures.
(2) Disconnect wire connector from back of door
lock switch.(3) Depress switch to LOCK position.
(4) Using an ohmmeter, test switch resistance
between Pins 2 and 3. Refer to Door Lock Switch
Test and (Fig. 4).
(5) Depress switch to UNLOCK position.
(6) Test resistance between Pins 2 and 3.
(7) If resistance values are not within the param-
eters shown replace the door lock switch.
Fig. 1 Sliding Door Lock Motor±Typical
Fig. 2 Front Door Lock Motor
8P - 2 POWER DOOR LOCKSNS
DESCRIPTION AND OPERATION (Continued)
MEMORY SEAT AND MIRROR SYSTEM
INDEX
page page
GENERAL INFORMATION
INTRODUCTION......................... 3
DESCRIPTION AND OPERATION
MEMORY SELECTOR SWITCHES............ 3
POSITION SENSING SEAT AND RECLINER
POTENTIOMETERS..................... 4
POWER SIDE VIEW MIRROR POSITION
SENSING............................. 3
SEAT AND RECLINER SWITCHES............ 4
DIAGNOSIS AND TESTING
CIRCUIT DESCRIPTION.................... 7DIAGNOSTIC MODE...................... 5
MEMORY SELECTOR SWITCHES............ 4
SEAT AND RECLINER POSITION SENSING.... 9
SIDE VIEW MIRROR SWITCH STUCK......... 4
SERVICE PROCEDURES
REMOTE KEYLESS ENTRY (RKE) DATA LINK . . . 9
REMOVAL AND INSTALLATION
MEMORY SWITCHES..................... 10
SEAT TRACK ASSEMBLY.................. 10
GENERAL INFORMATION
INTRODUCTION
Memory Seat and Mirrors system is available only
on Town and Country (Luxury Class) vehicles.
Refer to Group 8W, Wiring Diagrams for circuit
information and component locations. Refer to the
proper Body Diagnostic Procedures manual for addi-
tional diagnostic information.
The Memory Seat/Mirror Module (MSM Module) is
mounted under the driver's seat, on the inboard
upper track with Torx head screws. The MSM Mod-
ule provides the driver with an adjustable seat,
recliner, and power side view mirror positioning con-
troller that remembers stored positions and will
recall those positions on command.
The Memory Seat/Mirror Module reads all seat and
recliner switch inputs and operates the seat and
recliner motors in response to switch actuation. The
MSM Module monitors position sensing potentiome-
ters (mounted on the motors) for seat and recliner
positioning.
The MSM Module operates the power side view
mirror motors through solid state drivers (electronic
switches) in the recall mode only, and follows the
glass face position by means of rheostats built into
the motor pack assembly of the mirrors. Normal elec-
trical operation of the mirrors is accomplished by
actuation of the power mirror switch.
The Memory Seat/Mirror Module monitors the mem-
ory switches and has the capability to store desired
positions in non-volatile memory in response to a valid
input sequence. Refer to Memory Selector Switches (1,
2, and S) and Remote Keyless Entry (RKE) Data Link.
The memory seat/mirror module also can activate the
previously described motors in response to a recall
request from an individual memory switch.
The Memory Seat/Mirror Module monitors a data
link between the RKE receiver and the Body Control
Module (BCM) and will respond to stored information
or modify stored information when requested by a
valid data stream.
The Memory Seat/Mirror Module is connected to
the system through a seat wiring harness that inter-
faces will all of the components within the seat struc-
ture, and with electrical distribution wiring harness
connections to the non-seat mounted components.
The module operates the seat and recliner motors
through relays: four dedicated to track forward/rear-
ward, track front up/down, track rear up/down, and
recliner forward/rearward. A fifth relay controls the
direction of operation of those motors.
DESCRIPTION AND OPERATION
POWER SIDE VIEW MIRROR POSITION SENSING
The mirror switch on the instrument panel oper-
ates the outside rear view mirrors independently of
the memory seat/mirror module. The module acti-
vates the mirror motors only when in its recall mode.
The side view mirrors have position sensing rheo-
stats built into each side view mirror vertical and
horizontal motor assembly. These rheostats provide a
sense voltage to the memory seat/mirror module that
indicates where the mirror is moving to or where its
position is at when the module is activated but the
mirror motor is not moving.
MEMORY SELECTOR SWITCHES
The memory selector switches are mounted on the
driver's door trim panel within easy reach of the
driver. They provide a means to set or recall either of
NSPOWER SEATS 8R - 3
CAUTION: Some clutch packs appear similar, but
they are not the same. Do not interchange clutch
components, as they might fail.
HYDRAULICS
The hydraulics of the transaxle provide:
²Manual shift lever select function
²Main line pressure regulation
²Torque converter and cooler flow control
Oil flow to the friction elements is controlled
directly by four solenoid valves. The hydraulics also
include a unique logic- controlled solenoid torque con-
verter clutch control valve. This valve locks out the
1st gear reaction element with the application of 2nd,
direct, or overdrive gear elements. It also redirects
the 1st gear solenoid output so that it can control
torque converter clutch operation. To regain access to
1st gear, a sequence of commands must be used to
move the solenoid TCC control valve. This precludes
any application of the 1st gear reaction element with
other elements applied. It also allows one solenoid to
control two friction elements.
Small, high-rate accumulators are provided in each
controlled friction element circuit. These serve to
absorb the pressure responses, and allow the controls
to read and respond to changes that are occurring.
SOLENOIDS
The solenoid valves perform most control functions,
these valves must be extremely durable and tolerant
of dirt. For that reason hardened-steel poppet and
ball valves are used. These are free from any close
operating clearances. The solenoids operate the
valves directly without any intermediate element.
Direct operation means that these units must have
very high output. They must close against the size-
able flow areas and high line pressures. Fast
response is also required to meet the control require-
ments.
Two of the solenoids are normally-venting and two
are normally-applying; this was done to provide a
default mode of operation. With no electrical power,
the transmission provides 2nd gear in (OD), (3), or
(L) shift lever positions. All other transmission lever
positions will operate normally. The choice of 2nd
gear was made to provide adequate breakaway per-
formance while still accommodating highway speeds.
SENSORS
There are three pressure switches to identify sole-
noid application. There are two speed sensors to read
input (torque converter turbine) and output (parking
sprag) speeds. There is also a transmission range
sensor to indicate the manual shift lever position.
The pressure switches are incorporated in an assem-
bly with the solenoids. Engine speed, throttle posi-tion, temperature, etc., are also observed. Some of
these signals are read directly from the engine con-
trol sensors; others are read from a multiplex circuit
with the powertrain control module.
ELECTRONICS
The 41TE Transmission Control Module (TCM) is
located underhood in a potted, die-cast aluminum
housing. The module used is a new controller called
EATX III. The TCM has a sealed, 60-way connector.
ADAPTIVE CONTROLS
These controls function by reading the input and
output speeds over 140 times a second and respond-
ing to each new reading. This provides the precise
and sophisticated friction element control needed to
make smooth clutch-to-clutch shifts for all gear
changes. The use of overrunning clutches or other
shift quality aids are not required. As with most
automatic transaxles, all shifts involve releasing one
element and applying a different element. In simpli-
fied terms, the upshift logic allows the releasing ele-
ment to slip backwards slightly. This ensures that it
does not have excess capacity. The apply element is
filled until it begins to make the speed change to the
higher gear. The apply pressure is then controlled to
maintain the desired rate of speed change. This con-
tinues until the shift is made. The key to providing
excellent shift quality is precision. For example, the
release element for upshifts is allowed to slip back-
wards slightly. The amount of that slip is typically
less than a total of 20 degrees. To achieve that pre-
cision, the TCM learns the traits of the transaxle
that it is controlling. It learns the release rate of the
releasing element and the apply time of the applying
element. It also learns the rate at which the apply
element builds pressure sufficient to begin making
the speed change. This method achieves more preci-
sion than would be possible with exacting tolerances.
It can also adapt to any changes that occur with age
or environment.
For kickdown shifts, the control logic allows the
releasing element to slip. Then controls the rate at
which the input (and engine) accelerate. When the
lower gear speed is achieved, the releasing element
reapplies to maintain that speed until the apply ele-
ment is filled. This provides quick response since the
engine begins to accelerate immediately. This also
provides a smooth torque exchange since the release
element can control the rate of torque increase. This
control can make any powertrain feel more respon-
sive without increasing harshness.
Adaptive controls respond to input speed changes.
They compensate for changes in engine or friction
element torque and provide good, consistent shift
quality for the life of the transaxle.
NSTRANSAXLE AND POWER TRANSFER UNIT 21 - 73
DESCRIPTION AND OPERATION (Continued)