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.

E53 Only: 

Remove heater bulkhead.

Z3, E39, E46, E53: 

Remove cover for ignition coils.

Detach plug of wiring harness for ignition coils from DME control unit. This operation is described in 12 14 550 REPLACING CONTROL UNIT (DIGITAL MOTOR ELECTRONICS) (M62, M54)  . Disconnect plug connection of wiring harness for ignition coils in electronics box.

Detach grounding strap (2) of cable duct from connecting plate of ignition coils between cylinders 2 and 3.

Fig 1: Detaching Grounding Strap

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Unlock plug (1) and detach from ignition coils.

Unlock cable strip (2) and remove towards top.

Fig 2: Unlocking Plug And Detaching From Ignition Coils

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E53 Only: 

Remove water reservoir for windshield washer system. Refer to 61 71 061 REPLACING FLUID TANK FOR WINDSHIELD WASHER SYSTEM .

Remove cable (1) with profile seal from partition wall (3).

Unclip cable (2) from partition wall (3).

Release screw connection of partition wall (3) with body.

Remove partition wall (3).

Fig 3: Removing Partition Wall

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Pull profile seal (1) out of electronics box.

Release locks (2).

Remove strip (3).

Pull out profile seal (4).

Installation: 

To prevent leaks, you must install profile seals (1 and 4) correctly.

Fig 4: Pulling Profile Seal Out Of Electronics Box

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Z3, E46, E53 And E39: 

Check stored fault messages.

Rectify faults.

Then clear fault memory.