Before Changing A Control Module

Overview
Experience has shown that the majority of control modules returned for repair or replacement under warranty are in perfect working order. In these cases. replacement of the control module has obviously not cured the fault. Therefore, go through the following points carefully before definitely deciding to replace the control module:
1. Check all grounding points and the control module's power supply.

2. Use the diagnostics instrument to check that all test readings are plausible. (Several test readings can affect a particular function.)

3. Use the diagnostics instrument to check that all activated functions are in fact activated. (An output circuit fault can affect another function.)





4. If the fault persists the control module will have to be changed.

5. When handling control modules, it is important to ground yourself first by touching the car's engine, for instance. Avoid touching the control module's connecting pins.