Situation:

The expanded and comprehensive self-diagnostics of the DME M1.3 control unit may at times set fault code 01 unnecessarily.

This occurs as a system response to a negative voltage surge which migrates into the programming circuit of the DME (pin 39) via the ground connection made at pin 18 of the diagnostic connector with the old style cap installed. Later style caps (P/N 12 52 1 724 690) are designed to prevent this condition from occurring.

The previous version of this S.I. had advised you to remove pin 18 out of the diagnostic connector. With the advent of uncoded control units that need encoding via the MoDiC, the pin 18 removal procedure caused the situation that Motronic control units could not be encoded, since pin 18 carries part of the encoding information.