12 51 001 Replacing wiring harness section for engine (M54)

WARNING: This page does not describe the selected car, but rather 17 other vehicles, including the 2006 BMW 330Ci, 2006 BMW 325Ci, 2005 BMW 330xi, 2005 BMW 330i, and 2005 BMW 330Ci. However, it is still accessible from the selected car via links, so may be relevant.

Interrogate fault memory of DME control unit.

Switch off ignition.

Follow instructions for disconnecting and connecting battery. See 12 00... Instructions for disconnecting and connecting battery

Disconnect battery negative lead from battery.

WARNING: Scalding hazard!
Only perform these tasks on an engine that has cooled down.

E53 and E46:

Remove reinforcement plate.

Remove underbody protection.

E53, E46, E39:

Detach plug (1) from oil level sensor.

Unclip cable from cable holder (2) and lay upwards.

Fig 1: Detaching Plug From Oil Level Sensor

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When fitted:

Remove vacuum tank for exhaust flap.

Unlock plug (1) and detach from pulse generator for crankshaft.

Fig 2: Unlocking Plug

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Release nuts (1).

Detach leads (2) from starter motor.

Fig 3: Releasing Nuts

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Unlock plug (1) and detach from coolant temperature sensor. Release cable tie (2).

Fig 4: Unlocking Plug & Detaching From Coolant Temperature Sensor

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Disconnect plug connection (1).

E53 only:

Release cable tie (2) on transmission housing and disconnect cable (3).

Fig 5: Disconnecting Plug Connection

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Unlock plug (1) and detach from reverse gear switch.

Fig 6: Unlocking Plug & Detach From Reverse Gear Switch

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E53 and E46 only:

Remove heater bulkhead. See 51 71 080 REMOVING AND INSTALLING/REPLACING HEATER BULKHEAD

E53, E46 and E39:

Unclip plug connections (1) on oxygen control sensors from holders and disconnect.

Fig 7: Unclipping Plug Connections On Oxygen Control Sensors

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E53 only:

Disconnect all plugs in control unit box.

Unlock cable holders (2).

Remove cables (1) from cable holders (2).

Release screws (3).

Remove holder (4).

Fig 8: Removing Cables From Cable Holders

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Release nut.

Remove grounding cables from ground support point.

Detach profile seal (1) towards top.

Installation:

To prevent leaks, you must install profile seals correctly.

Fig 9: Detaching Profile Seal Towards Top (1 Of 2)

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Detach profile seals (1) towards top.

Installation:

To prevent leaks, you must install profile seals correctly.

Fig 10: Detaching Profile Seal Towards Top (2 Of 2)

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E46 only:

Pull off sealing strip (1).

Fig 11: Removing Sealing Strip

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Withdraw vacuum line and battery positive lead from assembly compartment partition wall.

Turn fasteners (1) through 90°. This unlocks the fasteners (1). Remove assembly compartment partition wall (2) towards top.

Installation:

To ensure watertightness, it is essential to install profile seals of vacuum line, battery positive lead and engine wiring harness correctly.

Fig 12: Removing Assembly Compartment Partition Wall Towards Top

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Release screws (1).

Installation:

Remove cover from electronics box.

Fig 13: Releasing Screws

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Pull out profile seal (1).

Unlock plug (2) and disconnect.

Fig 14: Unlocking Plug

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E39 only:

Disconnect all plugs in control unit box.

One part of this operation is described in 12 14 550 REPLACING CONTROL MODULE (DME) .

Remove air duct on left and right.

Release fasteners (1).

Detach rubber strip (2).

Fig 15: Removing Rubber Strip

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Release fasteners (1).

Remove firewall panel (2).

Fig 16: Removing Firewall Panel

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E53, E46 and E39:

Remove throttle assembly. See 13 54 030 REMOVING AND INSTALLING/SEALING THROTTLE ASSEMBLY (M54)

Remove intake air manifold. See 11 61 050 REMOVING AND INSTALLING INTAKE AIR MANIFOLD (M54)

Unlock plug (1) and detach from alternator.

Fig 17: Unlocking Plug & Detaching From Alternator

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Unlock plug (1) on pulse generator of inlet camshaft and detach from cable duct (2).

Fig 18: Unlocking Plug On Pulse Generator Of Inlet Camshaft

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Unlock plug (1) and detach from solenoid valve of VANOS adjustment unit.

Unlock plug (2) and detach from pulse generator for exhaust camshaft.

Fig 19: Unlock plug (2) and detach from pulse generator for exhaust camshaft

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Unlock plug (1) and detach from thermostat housing.

Fig 20: Unlocking Plug & Detaching From Pulse Generator For Exhaust Camshaft

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NOTE: Interrogate fault memory of DME control unit.
Check stored fault messages.
Rectify faults.
Then clear fault memory.