Replacing Wiring Harness Section For Engine

Replacing Wiring Harness Section For Engine (M54)

Interrogate fault memory of DME control unit.
Switch off ignition.
Follow 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.

CAUTION: The section "Removing and installing reinforcement plate" contains important installation instructions.

Remove underbody protection.

E53, E46, E39:







Detach plug (1) from oil level sensor.
Unclip cable from cable holder (2) and lay upwards.

When fitted:







Remove vacuum tank for exhaust flap.
Unlock plug (1) and detach from pulse generator for crankshaft.







Release nuts (1).
Tightening torque.
4AZ Electrical leads to starter
M5 5 Nm
M6 7 Nm
M8 13 Nm

Detach leads (2) from starter motor.







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







Disconnect plug connection (1).
E53 only:
Release cable tie (2) on transmission housing and disconnect cable (3).







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

E53 and E46 only:
Remove heater bulkhead.

E53, E46 and E39:







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

E53 only:
Disconnect all plugs in control unit box.
One part of this operation is described in the section "Replacing control unit".







Unlock cable holders (2).
Remove cables (1) from cable holders (2).
Release screws (3).
Remove holder (4).







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.







Detach profile seals (1) towards top.

Installation:
To prevent leaks, you must install profile seals correctly.

E46 only:







Pull off sealing strip (1).







Withdraw vacuum line and battery positive lead from assembly compartment partition wall.
Turn fasteners (1) through 90 degrees. 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.







Release screws (1).

Installation:
Tightening torque 3 Nm


Remove cover from electronics box.







Pull out profile seal (1).
Unlock plug (2) and disconnect.

E39 only:
Disconnect all plugs in control unit box.
One part of this operation is described in the section "Replacing control unit".
Remove air duct on left and right.







Release fasteners (1).
Detach rubber strip (2).







Release fasteners (1).
Remove firewall panel (2).

E53, E46 and E39:
Remove throttle assembly.
Remove intake air manifold.







Unlock plug (1) and detach from alternator.







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







Unlock plug (1) and detach from solenoid valve of VANOS adjustment unit.
Unlock plug (2) and detach from pulse generator for exhaust camshaft.







Unlock plug (1) and detach from thermostat housing.

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