12 51 001 Replacing wiring harness section for engine (N14, N18)

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

IMPORTANT: Gaiter and charge air hoses with clamp fastenings must be installed dry and free from grease!
Sealing surfaces and connecting branches must be dry and free from grease.
If gaiter and charge air hoses with clamp fastenings are not installed dry and free from grease, this may result in exhaust turbocharger failure!

Necessary preliminary tasks:

Read out the fault memory of the DME control unit.
Switch off ignition.
Disconnect BATTERY EARTH LEAD .
Remove intake plenum. See REMOVING INTAKE PLENUM (N14) or REMOVING INTAKE PLENUM (N18) .
Remove SOUND GENERATOR .
Remove right ENGINE MOUNT .
All-wheel drive vehicle only:
Remove transfer box.

Unlock and remove cover (1).

Fig 1: Identifying Cover

Courtesy of BMW OF NORTH AMERICA, INC.

Unlock and detach the two rear connectors (1).

Fig 2: Identifying Connector

Courtesy of BMW OF NORTH AMERICA, INC.

Release clamps (2).

Pull off gaiter (3) and remove it.

Remove intake pipe (4).

Installation note:

Install gaiter (3) dry and free from grease.

Connecting branch on exhaust turbocharger must be dry and free from grease.

Fig 3: Removing Intake Pipe

Courtesy of BMW OF NORTH AMERICA, INC.

Unlock and pull off connectors (1 and 3).

Unlock and detach vacuum line (2).

Carefully pull cable channel (4) upward away from the holder.

Fig 4: Pulling Cable Duct Upwards

Courtesy of BMW OF NORTH AMERICA, INC.

Work step	Note
Unlock and pull off connector for coolant temperature sensor.	N14
Unlock and pull off connector for ignition coils See 12 13 511 REPLACING IGNITION COILS (N14) or 12 13 511 REPLACING IGNITION COILS (N18)
Release ground connection from cylinder head	Tightening torque 12 51 1AZ .
Unlock and pull off connector for control sensor
Unlock and pull off connector for electric valve from exhaust turbocharger
Unlock and pull off connector for auxiliary water pump
Unlock and pull off connector for monitoring sensor
Unlock and pull off connector for coolant thermostat
Unlock and pull off connector for high pressure pump
Release connector for high pressure sensor and remove.
Unlock and pull off connector for knock sensor
Unlock and pull off connector for crankshaft sensor
Unlock and pull off connector for injectors
Unlock and pull off connector for solenoid valve
Unlock and pull off connector for temperature and charging pressure sensor
Unlock and pull off connector for friction wheel

NOTE: Check stored fault messages.
Clear diagnostic fault entries from fault memory.