Engine Control Module: Testing and Inspection

Verifying ECM Failure:

When all tests have been carried out according to the relevant programme without any faults having been found, it is natural to assume that the ECM is at fault.

In view of the fact that the ECM is an exceptionally high quality component and also extremely expensive, it is important to verify the diagnosis as far as possible.

Therefore, go through all the points very carefully before definitely pointing to the ECM as the cause of the fault.

1 Check once again that every single point in the fault diagnosis program of the relevant diagnostic trouble code has been carried out.

2 Study the schematic of the circuit in question and make sure you understand how it works.

3 Check all ground points. If you have already done this, do it once again.

4 Check the voltage supplied to the ECM.

5 Go once more through each point listed under "Points to Remember When Diagnosing Faults." Points to Remember When Diagnosing Faults

6 If the original fault still persists in spite of this, then the ECM will have to be replaced.