Transmission Control Module (TCM) Operation

OPERATION

CAUTION: Disconnection of Engine Control Module (ECM) multiplugs may introduce other fault codes. Following rectification and reconnection, please ensure that no induced codes exist.

NOTE:
^ Should the Transmission Control Module (TCM) fail, please ensure that the control housing cooling fan is operating correctly. Failure of the cooling fan MUST be rectified before renewing the TCM and details of a fan failure should accompany the returned TCM.
^ The TCM performs several 'self check' procedures to ensure correct operation. It is possible due to the nature of these faults that the module will fail to communicate with other nodes. However, condemnation of the TCM should not take place until any Controlled Area Network (CAN) or power supply related issues have been resolved.

MONITORING PROCEDURE
There are three (3) self check procedures for the TCM.
1. Check on Read Only Memory (ROM) by calculating a checksum and comparing this with a known stored value.
2. Check on non-volatile diagnostic memory by writing a test pattern and then reading it back.
3. Internal 'watchdog' hardware to check whether the TCM has crashed.