12 51 001 Replacing wiring harness section for engine (N54)

WARNING: This page is about a different car, the 2016 BMW Z4, 2015 BMW Z4, and 2014 BMW Z4. However, it is still accessible from the selected car via links, so may be relevant.

Attention!

Read and comply with notes on PROTECTION AGAINST ELECTROSTATIC DISCHARGE (ESD PROTECTION) .

Necessary preliminary tasks:

Read out the fault memory of the DME control unit.
Switch off ignition.
Disconnect BATTERY EARTH LEAD .
Partially remove WIRING HARNESS for injectors and ignition coils.
Remove INTAKE PLENUM .
Remove front UNDERBODY PROTECTION .
Remove rear UNDERBODY PROTECTION .

Release bolts along line (1).

Tightening torque 12 90 1AZ .

Remove electronics box cover.

Fig 1: Identifying Control Unit Bolts (DME)

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Unlock battery positive lead (1), detach and lay to one side.

Release locks (2) in direction of arrows and pull control unit upwards slightly.

Fig 2: Removing Control Unit Locks

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Pull control unit (1) upwards slightly until plug (2) can be released from control unit in direction of arrow.

Unlock plug (2) and detach from control unit (1).

Fig 3: Removing Control Unit Plug Connection

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Unlock and detach all connectors from engine wiring harness in electronics box (1).

Unclip rubber grommet hold-down devices (2) and (3) and release engine wiring harness from electronics box.

Installation note:

Make sure rubber grommets are correctly fitted (watertightness).

Fig 4: Identifying Electronics Box And Rubber Grommet Hold Down Devices

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Long connector:

Press in retaining lugs and withdraw lock (1) in direction of arrow from connector housing.

Fig 5: Pressing Connector Lock Retaining Lugs

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Press locking tabs (1) in direction of arrow and pull contact carrier (2) out of housing.

Fig 6: Pressing Contact Carrier Locking Tabs (Long Connector)

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Press locking tab (1) in direction of arrow and pull contact carrier (2) out of housing.

Fig 7: Removing Contact Carrier From Housing

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Unlock locking tabs (1) in direction of arrow and pull contact carrier (2) out of housing.

Fig 8: Unlocking Contact Carrier Locking Tabs

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Short connector:

Press in retaining lugs (1) and withdraw lock (2) in direction of arrow from connector housing.

Fig 9: Removing Short Connector Locks From Plug Housing

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Press locking tabs (1) in direction of arrow and pull contact carrier (2) out of housing.

Fig 10: Pressing Contact Carrier Locking Tabs (Long Connector)

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Unlock locking tabs (1) in direction of arrow and pull contact carrier (2) out of housing.

Fig 11: Unlocking Contact Carrier Locking Tabs

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Unclip cable duct upper section (1) and expose wiring harnesses.

Release screws (1).

Tightening torque 12 90 4AZ .

Remove cable channel (2).

Fig 12: Identifying Cable Channel And Screws

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Work step	Note
Unlock plug connections on control sensors and disconnect
Unlock connector on heating element and disconnect
Unlock connector on alternator and disconnect
Unlock and disconnect the connector from the pressure sensor on the intake plenum.
Unlock connector on throttle body and disconnect
Unlock plug connection on knock sensors and disconnect
Unlock connector on crankshaft sensor and disconnect
Unlock connector on starter motor and disconnect
Unlock connector on crankshaft pulse sensor and disconnect
Unlock connector on high pressure pump and disconnect
Unlock connector on air conditioning compressor and disconnect
Unlock connector on transmission and disconnect
Unlock connector on tank venting valve and disconnect
Unlock plug connections on monitoring sensors and disconnect
Unlock connector on oil condition sensor and disconnect
Unlock connector on intake air temperature sensor and disconnect
Unlock connector on oil pressure sensor and disconnect
Unlock connector on coolant temperature sensor and disconnect
Unlock connector on intake camshaft pulse sensor and disconnect
Pull off connector on solenoid valves and disconnect
Unlock connector on exhaust camshaft pulse sensor and disconnect
Unlock plug on both pressure converters and disconnect
Unlock connector on coolant thermostat and disconnect
Unlock plug on coolant pump and disconnect
Release ground connection on crankcase lower section Tightening torque 12 90 3AZ .

Release wiring harness from clips and retainers.

Feed out wiring harness and remove.

Installation note:

Check the wiring harness installation arrangement.

Check that the plug connections are correctly fitted.

NOTE: Check stored fault messages.
Delete the fault memory.