Chrysler Stratus LHD 1997, Interactive Electronic Service Manual

Page: 1176 / 1534

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.
TORQUE MANAGEMENT
Most 41TE transaxles utilize torque management.
Torque management is a unique function of the Pow-
ertrain Control Module (PCM). The PCM receives
output signals from the Transmission Control Module
(TCM) and many various engine sensors. The PCM
evaluates these signals and decides if it is necessary
to decrease the output of the engine’s torque. This
reduction in torque does not interfere with the nor-
mal operation of the vehicle. This reduction in torque
will prolong the life of the drivetrain components.
Torque reduction is not noticeable in normal driving
functions. The torque reduction function shuts off
above 16 MPH.
ON-BOARD DIAGNOSTICS
This vehicle utilizes a diagnostic system called
OBDII. The powertrain control module communicates
with the Transmission Control Module. Whenever
the transaxle sets a fault in the Transmission Con-
trol Module (dependent on which fault is set), the
powertrain control module will turn on a MIL (Mal-
function Indicator Lamp) on the instrument cluster.
By reading the code in the powertrain control module
it will tell you where the fault occurred. If the fault
occurred in the transaxle, the controller will read a
CODE 45. For further information regarding OBDII,
refer to Group 25, Emission Systems.
These controls provide comprehensive, on-board
transaxle diagnostics. The information available can
aid in transaxle diagnosis. For example, apply ele-
ment buildup rate indicates solenoid performance.
Also included are self diagnostic functions. Self diag-
nostics allow the technician to test the condition of
the electronic controls. The Transmission Control
Module continuously monitors its critical functions. It
also records any malfunctions, and the number of
engine starts since the last malfunction. This allows
the technician to use the information in the event of
a customer complaint.
TRANSMISSION CONTROL MODULE
Do not interchange Transmission Control Modules
with previous year transmission control modules. If a
same year TCM is being used from a different vehi-
cle, the following procedures must be performed:
•
Quick Learn Procedure
•
Torque Converter Clutch Break-in Procedure
•
Electronic Pinion Factor Procedure
The Transmission Control Module is located on the
right inner fender panel, in the engine compartment.
It is held in place by four mounting screws.
NOTE: If the Transmission Control Module has
been replaced, the following procedures must be
performed:
•
Quick Learn Procedure: This procedure will
allow the transmission control module to learn the
characteristics of the vehicle.
•
Electronic Pinion Factor Procedure: This proce-
dure will reprogram the TCM to compensate for dif-
ferent tire sizes and final drive ratios.
•
Converter Clutch Break-In Procedure: This pro-
cedure will reset the torque converter clutch status.
SHIFTER/IGNITION INTERLOCK
The Shifter/Ignition Interlock, is a mechanically
cable operated system. It interconnects the automatic
transmission floor mounted shifter to the steering
column ignition switch. The interlock system locks
the floor mounted shift lever into the PARK position
whenever the ignition switch is in the LOCK or
ACCESSORY position. When the key is in the OFF
or RUN position the shifter is unlocked and will
move into any position. The interlock system also
prevents the ignition switch from being turned to
JA
TRANSAXLE 21 - 45
DESCRIPTION AND OPERATION (Continued)