Before Changing A Control Module
Experience shows that most control modules returned for repair while under warranty are not faulty. In such cases, changing the control module does not rectify the fault. Go through the following steps before changing a control module.
1 Check all grounding points and the supply of power to the control module.
2 Check with a diagnostic tool that all test values are reasonable. (A single function can be affected by several test values).
3 Check with a diagnostic tool that all functions are operating. (A fault in one output circuit can affect another output circuit).
4 If the fault persists, the control module must be changed.
5 It is important to ground your own body, by touching the engine for example, before handling a control module. Never touch the control module pins.