Transmission Control Module (TCM) - 8HP45

P1634-TCM INTERNAL - INTERNAL WATCHDOG PERFORMANCE

For a complete wiring diagram Refer to the Wiring Information.

Theory of Operation

The purpose of the diagnostic is to monitor the presence of all inhibit path functionality that are needed to bring the Transmission Control Module (TCM) to a safe state in case of a failure. Proper inhibit path operation means that the TCM is able to switch off a single output stage and it is able to switch off all output stages by, switching off the output stages power supply (high side switch), activating the peripheral reset line or deactivating the peripheral clock.

- When Monitored:
Continuously with the ignition switch in the run position.

- Set Condition:
If the TCM microprocessor internal watchdog detects an error.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. 8HP45 Pre-Diagnostic Troubleshooting Procedure

TRANSMISSION CONTROL MODULE

View repair

Repair

- Using the schematics as a guide, check the Transmission Control Module A (TCMA) terminals for corrosion, damage or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace and program the TCMA. Valve Body - Removal.
- Perform the TRANSMISSION VERIFICATION TEST. Verification Tests