12 51 100 Replacing wiring harness section for ignition coils (M54)
Interrogate fault memory of DME control unit.
Switch off ignition.
Follow instructions for disconnecting and connecting battery. Refer to 12 00 ... INSTRUCTIONS FOR DISCONNECTING AND CONNECTING BATTERY .
Disconnect battery negative lead from battery.
Z3, E39, E46, E53
Remove cover for ignition coils.
Detach plug of wiring harness for ignition coils from DME control unit. Refer to 12 14 550 REPLACING CONTROL UNIT (M54 / S54) . Disconnect plug connection of wiring harness for ignition coils in electronics box.
Note. Do not remove DME control unit.
Detach grounding strap (2) of cable duct from connecting plate of ignition coils between cylinders 2 and 3.
Scheme 6
Unlock plug (1) and detach from ignition coils.
Scheme 7
Unlock cable strip (2) and remove towards top.
E46 and Z3 only
Note. Shown on the E46. The same procedure applies to the Z3.
Pull off sealing strip (1).
Remove cable (3) together with profile seal (2) from partition wall towards top.
Scheme 8
Installation
To prevent leaks, you must install profile seal (2) correctly.
Z3, E46, E53 and E39
Note. Interrogate fault memory of DME control unit.
Check stored fault messages.
Rectify faults.
Then clear fault memory.