12 51 001 Replacing wiring harness section for engine (N52)

Necessary preliminary tasks: 

• Read out fault memory of DME control unit
• Switch off ignition
• Follow Instructions For Disconnecting And Connecting Battery 

  Disconnect Battery Negative Lead from battery and lay to one side

• Remove lower section of Microfilter Housing
• Remove Intake Air Manifold
• Remove Cylinder Head Cover

Unlock fasteners (1) from below and slide upwards approx. 10 mm.

Unlock locks (2) in direction of arrow.

Remove cover (3).

Fig 1: Identifying Wiring Harness Cover, Fasteners And Locks

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Unlock plug on control unit and disconnect.

Unlock tab (1), pull contact carrier (2) in direction of arrow out of housing.

Fig 2: Identifying Control Unit Tab And Contact Carrier

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Unlock slide (2) in bore holes (1) and pull out of housing.

Unlock tab (3), pull contact carrier (4) in direction of arrow out of housing.

Unlock and disconnect all plug connections of engine wiring harness section in electronics box.

Fig 3: Identifying Wiring Harness Slide, Bore Holes, Tab And Contact Carrier

Courtesy of BMW OF NORTH AMERICA, INC.

Illustration shows cylinder head cover. 

Release screws and remove holder (1).

For tightening torque refer to 12 52 1AZ in 12 52 PLUG CONNECTIONS, TERMINALS, LOOSE PARTS .

Fig 4: Identifying Holder With Screws

Courtesy of BMW OF NORTH AMERICA, INC.