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Procedure prior to replacement of a controlmodule

Procedure prior to replacement of a control module


If it has not been possible to find any fault after everything has been checked in accordance with the diagnostic procedure for the relevant diagnostic trouble code, and separate checking of component operation has also been carried out, it is natural to assume that the control module is defective.

In view of the fact that the control module is manufactured to extremely exacting standards of quality, and also because it is a rather expensive component, every effort should be made to ensure that the diagnosis is as accurate as possible.

Therefore, run through the following points before definitely settling on the TCS control module as the cause of the fault.


1. Check once again that all points in the relevant diagnostic procedure have been carried out correctly.

2. Study the schematic diagram of the relevant circuit until you understand how it works. If necessary, consult appropriate parts of the technical description and suitable sections of Service Manual 3:2 "Electrical system, system diagrams, operation and fault- tracing".

3. Check the control module's ground connections once again and also check that the relevant grounding points are good and correct.


4. Check the control module's voltage supply.

5. Also go through the points in "Points to note when diagnosing faults" and make sure that you have not overlooked anything.

6. If the original fault still persists, the TCS control module will have to be changed.

Do not forget to program the control module for the car variant in question.


Handling control modules


All control modules are more or less sensitive to static electricity and, if handled carelessly or incorrectly, may be damaged so seriously that they no longer work properly. It is therefore important to ensure that the following rules are observed at all times when a control moodule is removed or replaced for any reason.

Note

Avoid unplugging or removing a control module unless absolutely necessary.

Never touch the connector pins and never place the control module in such a way that the connector pins may come into contact with foreign objects.

Before unpacking a new control module, ground the packaging to the car body. Open the packaging as shortly as possible before installing the control module.

Avoid wearing clothes made of synthetic (man-made) fibres.

When handling or working on control modules it is important to ground yourself from time to time. This is particularly important when you have been sitting in the car, when changing your position, or when moving round the car. It is even more important in a climate with extremely dry air (e.g. during the winter in cold markets).

Furthermore, always handle control modules which are suspected of being defective in the same manner. This will greatly improve the chances of determining the cause of the fault.