12 51 001 Replacing wiring harness section for engine (N57 D30 O/T 1)
Necessary preliminary tasks:
- Read out the fault memory of the DDE control unit.
- Switch off ignition.
- Disconnect BATTERY NEGATIVE LEAD .
- Remove front right SUSPENSION CROSS-BRACE
- Remove rear right SUSPENSION CROSS-BRACE
- Remove SOUND INSULATION for bulkhead on left
- Remove ACOUSTIC COVER at rear.
- Remove front UNDERBODY PROTECTION .
- Remove rear UNDERBODY PROTECTION .
- Remove bottom ACOUSTIC COVER .
- 4WD vehicles only:
Remove STIFFENING PLATE
Release screws (1).
Tightening torque 12 90 4AZ .
Release clamp (2).
Remove cover (3) from supplementary electronics box.
Disconnect all connectors on carrier plate (1) from engine wiring harness and release from supplementary electronics box.
Installation note:
Make sure rubber grommets are correctly fitted (watertightness).
Unclip grommet hold-down device (1).
Release wiring harnesses (2) from bulkhead.
Release wiring harness (1) from retainers (2).
Release screws (1).
Tightening torque 12 90 2AZ .
Remove electronics box cover (2).
Unlock all connectors (1) from control unit and disconnect.
Unclip grommet hold-down device (2) and remove.
Release rubber grommets (3) from the electronics box. Lay wiring harnesses to one side.
Installation note:
Make sure grommets are correctly fitted (watertightness).
Slacken nut (1).
Tightening torque 12 52 7AZ .
Remove earthing cables (2).
Release screws (1).
Remove cable channel (2) from the cylinder head cover. To do this unlock and detach connectors (3) and (4).
Slide cable channel to one side.
| Unlock and disconnect following connectors and lines | Note |
|---|---|
| Unlock connector on hot film air mass meter and disconnect | |
| Unlock connector on exhaust turbocharger and disconnect | |
| Unlock connector on all electric changeover valves on carrier plate and disconnect | 535 d and 640 d only |
| Unlock connector on both exhaust backpressure sensors and disconnect | |
| Unlock connector on both exhaust-gas temperature sensors and pull off | |
| Unlock connector on oxygen sensor and disconnect | |
| Unlock connector on vacuum electric changeover valve (exhaust-gas recirculation) and disconnect | |
| Unlock connector on exhaust-gas recirculation valve and disconnect | |
| Unlock connector on coolant temperature sensor and disconnect | |
| Unlock connector on intake plenum intake adjuster and disconnect | |
| Unlock connector on intake pressure sensor and disconnect | |
| Unlock connector on rail pressure sensor and disconnect | |
| Unlock connector on rail pressure regulating valve and disconnect | |
| Unlock connector on camshaft sensor and disconnect | |
| Unlock connector on alternator and disconnect | |
| Unlock connector on air conditioning compressor and disconnect | |
| Unlock connector on intake air temperature sensor and disconnect | |
| Unlock connector on oil pressure sensor and disconnect | |
| Unlock connector on starter motor and disconnect | |
| Unlock connector on transmission and disconnect | |
| Unlock connector on oil level sensor and disconnect | |
| Unlock connector on crankshaft sensor and disconnect | |
| Unlock connector on throttle body and disconnect | |
| Unlock connector on exhaust-gas recirculation temperature sensor and disconnect | |
| Unlock connector on high pressure pump and disconnect | |
| Unlock connector on fuel pressure/temperature sensor and disconnect | |
| Unlock connector on preheating control unit and remove |
Release wiring harness from clips and retainers.
Feed out wiring harness and remove.
Installation note:
Check wiring harness installation arrangement.
Check plug connections for correct fit.
Check stored fault message.
Clear diagnostic fault entries from fault memory.