Transmission Control Module (TCM)
OVERVIEWThe 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 DRBIII Scan Tool.
TCM PROGRAMMING
1 Procedure for flashing the transmission control module with MDS2.
NOTE: THE MDS2 IS REQUIRED TO PERFORM THIS FLASH UPDATE. THE MDS2 MUST BE OPERATING WITH THE LATEST RELEASE INSTALLED. FOLLOW THE PROMPTED FLASH INSTRUCTIONS ON THE MDS2.
2 Procedure for flashing the transmission control module with MDS.
NOTE: THE MDS IS REQUIRED TO PERFORM THIS FLASH UPDATE. THE MDS MUST BE OPERATING WITH THE LATEST RELEASE INSTALLED.
Perform the following procedure for the update:
1 Connect the MDS and DRBIII (Scan Tool) to the vehicle and power them up.
NOTE: FOR THE 2000 MODEL YEAR THE TCM CAN BE REPROGRAMMED FROM THE DIAGNOSTIC DATA LINK CONNECTOR.
2 Use the arrow keys on the DRBIII and from the MAIN MENU screen select MDS DIAGNOSTICS.
3 Use the arrow keys on the MDS and select DIAGNOSTIC MENU from the MDS screen, the press NEXT MENU.
4 Use the arrow keys on the MDS and select VEHICLE CONTROLLER PROGRAMMING, then press NEXT MENU.
5 Use the arrow keys and select PROGRAMMING OF ALL OTHER CONTROLLERS WITH MDS & DRBIII on the MDS, then press NEXT MENU.
6 Follow the steps presented on the MDS and DRBIII, which will allow the DRBIII to obtain the current part number of the PCM.
7 The MDS will display the description of the updatable PCM and/or TCM on the vehicle and the appropriate replacement part number(s). Select the description of the TCM, then press NEXT MENU to begin programming.
8 The MDS and DRBIII will prompt for any operator action needed during the remainder of the programming process. If both the PCM and TCM on the vehicle have already been updated, and NO UPDATES AVAILABLE message will be displayed. If this is the case, verify the Authorized Modification Labels attached to the TCM and near the Vehicle Emission Control Information (VECI) label. If the labels are not attached, proceed to step 9. Otherwise, end the procedure.
9 Type the necessary information on the Authorized Modification Label and attach the label near the VECI label.
10 Type the necessary information on the Authorized Software Update Label and attach it to the TCM and cover label with a clear plastic sticker.