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

WARNING: This page is about a different car, the 2003 BMW 525i, 2002 BMW 525i, 2001 BMW 525i, and 2000 BMW 528i. 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. Refer to 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. 13 32 051 REPLACING FUEL FILTER (M54)

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

Courtesy of BMW OF NORTH AMERICA, INC.

When fitted:

Remove vacuum tank for exhaust flap.

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

Fig 2: Detaching Plug From Pulse Generator

Courtesy of BMW OF NORTH AMERICA, INC.

Release nuts (1).

Tightening torque. Refer to ENGINE ELECTRICAL SYSTEM - TIGHTENING TORQUE .

Detach leads (2) from starter motor.

Fig 3: Detaching Leads From Starter Motor

Courtesy of BMW OF NORTH AMERICA, INC.

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

Fig 4: Detaching Plug From Coolant Temperature Sensor

Courtesy of BMW OF NORTH AMERICA, INC.

Disconnect plug connection (1).

E53 only:

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

Fig 5: Releasing Cable Tie & Disconnecting Cable

Courtesy of BMW OF NORTH AMERICA, INC.

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

Fig 6: Detaching Plug From Reverse Gear Switch

Courtesy of BMW OF NORTH AMERICA, INC.

E53 and E46 only:

Remove heater bulkhead.

E53, E46 and E39:

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

Fig 7: Disconnecting Oxygen Control Sensors Plug Connections

Courtesy of BMW OF NORTH AMERICA, INC.

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

Courtesy of BMW OF NORTH AMERICA, INC.

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 (1 Of 2)

Courtesy of BMW OF NORTH AMERICA, INC.

Detach profile seals (1) towards top.

Installation:

To prevent leaks, you must install profile seals correctly.

Fig 10: Detaching Profile Seal (2 Of 2)

Courtesy of BMW OF NORTH AMERICA, INC.

E46 only:

Pull off sealing strip (1).

Fig 11: Removing Sealing Strip

Courtesy of BMW OF NORTH AMERICA, INC.

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

Courtesy of BMW OF NORTH AMERICA, INC.

Release screws (1).

Installation:

Tightening torque. Refer to ENGINE ELECTRICAL SYSTEM - TIGHTENING TORQUE .

Remove cover from electronics box.

Fig 13: Removing Cover From Electronics Box

Courtesy of BMW OF NORTH AMERICA, INC.

Pull out profile seal (1).

Unlock plug (2) and disconnect.

Fig 14: Disconnecting Plug

Courtesy of BMW OF NORTH AMERICA, INC.

E39 only:

Disconnect all plugs in control unit box. Refer to 12 14 550 Replacing control unit (DME) (M52, M62, M54) .

Remove air duct on left and right.

Release fasteners (1).

Detach rubber strip (2).

Fig 15: Releasing Fasteners & Detaching Rubber Strip

Courtesy of BMW OF NORTH AMERICA, INC.

Release fasteners (1).

Remove firewall panel (2).

Fig 16: Releasing Fasteners & Removing Firewall Panel

Courtesy of BMW OF NORTH AMERICA, INC.

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: Detaching Plug From Alternator

Courtesy of BMW OF NORTH AMERICA, INC.

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

Fig 18: Detaching Pulse Generator Plug

Courtesy of BMW OF NORTH AMERICA, INC.

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: Detaching Plug From Solenoid Valve & Pulse Generator

Courtesy of BMW OF NORTH AMERICA, INC.

Unlock plug (1) and detach from thermostat housing.

Fig 20: Detaching Plug From Thermostat Housing

Courtesy of BMW OF NORTH AMERICA, INC.

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