12 51 001 Replacing wiring harness section for engine (N52K)
Necessary preliminary tasks:
- Read out fault memory of DME control unit
- Turn off ignition
- Disconnect BATTERY NEGATIVE LEAD
- Remove front UNDERBODY PROTECTION
- Remove rear UNDERBODY PROTECTION
- Partially remove WIRING HARNESS for ignition coils
- Remove INTAKE AIR MANIFOLD
Release bolts along line (1).
Tightening torque 12 90 1AZ .
Remove electronics box cover.
Unlock battery positive lead (1), detach and lay to one side.
Release locks (2) in direction of arrows and pull control unit upwards slightly.
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).
Unlock and detach all plugs 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:
Make sure rubber grommets are correctly seated (watertightness).
Long plug:
Press in retaining lugs and withdraw lock (1) in direction of arrow from plug housing.
Press locking tabs (1) in direction of arrow and pull contact carrier (2) out of housing.
Press locking tab (1) in direction of arrow and pull contact carrier (2) out of housing.
Unlock locking tabs (1) in direction of arrow and pull contact carrier (2) out of housing.
Short plug:
Press in retaining lugs (1) and withdraw lock (2) in direction of arrow from plug housing.
Press locking tabs (1) in direction of arrow and pull contact carrier (2) out of housing.
Unlock locking tabs (1) in direction of arrow and pull contact carrier (2) out of housing.
Unclip cable duct upper section (1) and expose wiring harnesses.
Unclip cable duct (1) and remove from cylinder head cover.
Unclip plug connection (1) from holder (2) and disconnect.
Unclip wiring harness from holder (2).
Unclip holder (2) from fuel rail and remove.
Detach connector strip (2) in direction of arrow.
Do not remove fuel rail (3) and fuel line (1).
| Work step | Note |
|---|---|
| Unlock plug connections on control sensors and disconnect | |
| Unlock plug on alternator and disconnect | |
| Unlock plug connection on knock sensors and disconnect | |
| Unlock plug on crankshaft sensor and disconnect | |
| Unlock plug on starter motor and disconnect | |
| Unlock plug on throttle valve assembly and disconnect | |
| Unlock plug connections on monitoring sensors and disconnect | |
| Unlock plug on oil condition sensor and disconnect | |
| Unlock plug on tank vent valve and remove | |
| Unlock plug on transmission and disconnect | |
| Unlock plug on air-mass meter and disconnect | |
| Unlock plug on differential-pressure sensor and disconnect | |
| Unlock plug on intake system servomotors and disconnect | |
| Unlock plug on eccentric shaft sensor and disconnect | |
| Unlock plug on solenoid valves and disconnect | |
| Unlock plug on coolant temperature sensor and disconnect | |
| Unlock plug on oil pressure sensor and disconnect | |
| Disconnect connector strip on fuel injectors | |
| Unlock plug on A/C compressor and disconnect | |
| Unlock plug on coolant thermostat and disconnect | |
| Unlock plug on hydraulic valve and disconnect | |
| Unlock plug on coolant pump and disconnect | |
| Release earth connection and remove Tightening torque 12 90 3AZ . |
Release wiring harness if necessary from clips and retainers
Feed out wiring harness and remove.
Installation:
Check wiring harness routing.
Check plug connections for correct seating.
clear fault memory.