General Information

The Transmission Control Module (TCM) is the controlling unit for all electronic operations of the transaxle. The TCM receives information from several inputs, and selects the operational mode of the transaxle. Some of the inputs are used only by the TCM, while others are shared with other control modules on the CCD Bus.

Shift schedule logic, which is programmed into the TCM, selects the appropriate shift schedules for operating conditions. This is to determine the desired gear range the transaxle must be operated in. The actual shift points within each shift schedule have been predetermined for the best transaxle operation, and are stored in the TCM's ROM memory.

Once a TCM is installed during service, the following procedures must be performed:
- Quick Learn Procedure - Allows the transmission control module to learn the characteristics of the vehicle
- Electronic Pinion Factor Procedure - Reprograms the TCM to compensate for different tire sizes and final drive ratios on 1993 and newer vehicles

The quick learn procedure is necessary to learn Clutch Volume Index (CVI). The TCM must learn the CVI of the transaxle if it is to be fully adaptive. The quick learn procedure simply speeds up the TCM learning process. The vehicle must still be driven and shifted several times in each gear range during the road test. This will fully utilize the TCM's adaptive memory capability. The quick learn procedure is accessed through transaxle diagnosis and performed by the DRB Scan Tool.

NOTE: The quick learn procedure works only on version 10 (or later) TCM's. Look at the module display on the DRB III scan tool

Emission regulations require the use of two labels after a flash update:
- Emission Modification Label
- Emission Part Number Modification Label

The following provides information on TCM identification and flash programming application:

1989 - 92
- Original controllers were non-finned and are non-flashable
- Replacement controllers have fins with four heat sinks and are flashable
- Unique communications on CCD Data Bus for these year models
- Requires the use of Miller CH 5500 flash kit

1993 - 95
- Original controllers were finned with four heat sinks and are flashable
- Replacement controllers have fins with four heat sinks and are flashable
- Unique communications on CCD Data Bus for these year models
- Requires the use of Miller CH 5500 flash kit

NOTE: Use TSB 18-24-95 to identify the few controller part numbers that are not flashable. This TSB also lists the 1990 vehicles that require a wiring modification to pin 49.

1996
- Original controllers were finned with seven heat sinks and are flashable
- Replacement controllers have fins with seven heat sinks and are flashable
- Unique communications on CCD Data Bus for these year models
- DOES NOT require the use of Miller CH5500 flash kit - Connection is made under the dash in the common DLC