Test Procedure Prior to ECM Replacement

Fig. 29 Action To Be Taken Before Replacing Control Module:

When all tests have been completed in accordance with the rectification program to the particular diagnostic trouble code or through service manual fault diagnosis, without any fault being traced, it is natural to assume that the electronic control module is faulty.

In view of the fact that the control module is a very high-quality an expensive component, It is important to diagnose the fault as far as possible. Carefully run through the following items before finally identifying the ABS control module as the cause of the fault.

1. Check the following:
- Correct wheel size
- All the wheels have the same height/width
- Correct air pressure in all the wheels
- No play in the wheel bearings

Check also once more that all the checks in the fault-tracing routine concerned have been carried out.

2. Study the wiring diagram of the circuit concerned and examine its function.

3. Check all the grounding points. If you have done this previously, do it once more. Check that power ground and signal ground are electrically and physically separated.

4. Check the power supply to the control module.

5. Clear the fault code. Test the car again. If the original fault remains despite this, the ABS control module must be replaced.