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Home >> BMW >> 2002 >> M Coupe >> Repair and Diagnosis >> Engine Performance >> Ignition System >> Engine Electrical System - Repair Instructions >> Troubleshooting >> 12 00... Working instructions for removing and installing electronic control unit >> Notes
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12 00... Working instructions for removing and installing electronic control unit: Notes

CAUTION: Disconnecting the vehicle battery will cancel the fault memories of control units.

2-door: initialization of power window drives is omitted, window lowering does not function with a disconnected battery, clamping protection is not effective.

For this reason, before disconnecting the battery, connect up BMW SERVICE TESTER or DIS. DIS: (select Expert mode) interrogate fault memory and print out fault messages stored in memory. BMW SERVICE TESTER: Interrogate fault memory and print out fault messages stored in memory. Investigate stored faults.

Ignition must always be switched off before disconnecting or connecting control-unit connectors.

Removal and installation of components, relays, fuse, etc. could cause the storage of faults in fault memories of control units capable of self-diagnosis. For this reason, fault memories must always be interrogated after working on the electrical system. Stored faults must be investigated and cancelled.