12 51 001 Replacing Wiring Harness Section For Engine (N51, N52K)

Necessary preliminary tasks: 

• Read out fault memory of DME control unit
• Switch off ignition
• Disconnect battery negative lead  . See 61 20 900 DISCONNECTING AND CONNECTING BATTERY NEGATIVE LEAD (CONVERTIBLE) or 61 20 900 DISCONNECTING AND CONNECTING BATTERY NEGATIVE LEAD (COUPE) .
• Remove intake air manifold  . See 11 61 050 REMOVING AND INSTALLING INTAKE AIR MANIFOLD (N51) .

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

Unlock locks (2) in direction of arrow.

Remove cover (3).

Fig 1: Identifying Fasteners & Locks

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Unlock plug (1) and remove.

Release grommet (2) from electronics box.

Installation: 

Make sure grommet (2) is correctly seated in housing (watertightness).

Unlock control unit (3) and raise slightly.

Fig 2: Identifying Grommet & Control Unit

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Unlock plugs (1) using slide in direction of arrow and disconnect.

Fig 3: Identifying Plugs

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Long plug:

Unlock plug on control unit and disconnect.

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

Fig 4: Pulling Contact Carrier Out Of Housing

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Short plug:

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 5: Pulling Contact Carrier Out Of Housing

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