Control Systems: Notes

WARNING: This page is about a different car, the 2003 Jaguar XJ8, 2003 Jaguar XJ, 2002 Jaguar XJ8, 2002 Jaguar XJ, and 2001 Jaguar XJ8. However, it is still accessible from the selected car via links, so may be relevant.

The TCM is located in the same housing as the ECM and is accessed in the same manner.

Fig 1: Locating TCM

Courtesy of JAGUAR CARS, INC.

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 CAN or power supply related problems have been resolved.

There are three self check procedures for the TCM.

Check on ROM by calculating a check sum and comparing this with a known stored value.
Check on non-volatile diagnostic memory by writing a test pattern and then reading it back.
Internal "watchdog" hardware to check whether the TCM has crashed.