(clutch or brake). Fill time adaptation is the ability of
the TCM to modify the time it takes to fill the shift
member by applying a preload pressure.
CONTROLLER MODES OF OPERATION
Permanent Limp-In Mode
When the TCM determines there is a non-recover-
able condition present that does not allow proper
transmission operation, it places the transmission in
permanent Limp-In Mode. When the condition occurs
the TCM turns off all solenoids as well as the sole-
noid supply output circuit. If this occurs while the
vehicle is moving, the transmission remains in the
current gear position until the ignition is turned off
or the shifter is placed in the 9P9 position. When the
shifter has been placed in 9P, 9 the transmission only
allows 2nd gear operation. If this occurs while the
vehicle is not moving, the transmission only allows
operation in 2nd gear.
Temporary Limp-In Mode
This mode is the same as the permanent Limp-In
Mode except if the condition is no longer present, the
system resumes normal operation.
Under Voltage Limp-In Mode
When the TCM detects that system voltage has
dropped below 8.5 volts, it disables voltage-depen-
dant diagnostics and places the transmission in the
temporary Limp-In Mode. When the TCM senses
that the voltage has risen above 9.0 volts, normal
transmission operation is resumed.
Hardware Error Mode
When the TCM detects a major internal error, the
transmission is placed in the permanent Limp-In
Mode and ceases all communication over the CAN
bus. When the TCM has entered this mode normal
transmission operation does not resume until all
DTCs are cleared from the TCM.
Loss of Drive
If the TCM detects a situation that has resulted or
may result in a catastrophic engine or transmission
problem, the transmission is placed in the neutral
position. Improper Ratio, Input Sensor Overspeed or
Engine Overspeed DTCs cause the loss of drive.
Controlled Limp-in Mode
When a failure does not require the TCM to shut
down the solenoid supply, but the failure is severe
enough that the TCM places the transmission into a
predefined gear, there are several shift performance
concerns. For instance, if the transmission is slip-
ping, the controller tries to place the transmission
into 3rd gear and maintain 3rd gear for all forward
drive conditions.
STANDARD PROCEDURE - TCM ADAPTATION
The adaptation procedure requires the use of the
DRBIIIt scan tool. This program allows the elec-
tronic transmission system to re-calibrate itself. This
will provide the proper baseline transmission opera-
tion. The adaptation procedure should be performed
if any of the following procedures are performed:
• Transmission Assembly Replacement
• Transmission Control Module Replacement
• Clutch Plate and/or Seal Replacement
• Electrohydraulic Unit Replacement or Recondi-
tion
(1) With the DRBIIIt, reset the Transmission
adaptives. Resetting the adaptives will set the adap-
tives to factory settings.
NOTE: Perform the Coast Down Adaptations first.
The Transmission Temperature must be greater
than 60°C (140°F) and less than 70°C (158°F). Fail-
ure to stay within these temperature ranges will
void the procedure.
(2) Drive the vehicle until the transmission tem-
perature is in the specified range.
(3) Perform 4 to 5 coast downs from 5th to 4th
gear and then 4th to 3rd gear.
NOTE: For Upshift adaptation, the Transmission
temperature must be greater than 60°C (140°F) and
less than 100°C (212°F). Failure to stay within these
temperature ranges will void this procedure.
(4) From a stop, moderately accelerate the vehicle
and obtain all forward gear ranges while keeping the
Engine RPM below 1800 RPM. Repeat this procedure
4 to 5 times.
(5) Obtaining 5th gear may be difficult at 1800
RPM. Allow the transmission to shift into 5th gear at
a higher RPM then lower the RPM to 1800 and per-
form manual shifts between 4th and 5th gears using
the shift lever.
(6) The TCM will store the adaptives every 10
minutes. After completion of the adaptation proce-
dure make sure the vehicle stays running for at least
10 minutes.
(7) It is possible to manually store the adaptives
under the 10 minute time frame using the DRBIIIt
Store Adaptives procedure.
8E - 8 ELECTRONIC CONTROL MODULES VA
TRANSMISSION CONTROL MODULE (Continued)
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