Before Changing A Control Module

ACTIONS BEFORE CHANGING A TCM
When all checks have been carried out as specified under each fault code or under separate function checks without any faults being detected, it is natural to assume that the TCM is faulty.

Taking into account the fact that the TCM is a very high quality component and is also a very expensive component, it is important to ensure as far as possible that the diagnosis is correct.

Go through the following points very carefully before you definitely conclude that it is the TCM which is the cause of the fault.

1. Check once again that all the points in the fault tracing list for the fault in question have been carried out.

2. Study the wiring diagram for the circuit in question and make sure that you understand how it works. If necessary, use the relevant parts of the technical description and the description of the electrical functioning.

3. Check the TCM's ground connections once again and check that all current grounding points have the correct ground connection.

4. Check the TCM power supply.

5. Also go through the points at "Diagnostic Charts/Diagnostic Trouble Code (DTC) Charts/Guide Lines" and check that you have not missed anything. Guidelines.

6. If the original fault remains in spite of all this, a new TCM must be fitted.

Also read the information at "Handling of TCM's". Handling of Control Modules