12 51 001 Replacing wiring loom section for engine (N47 D20 O 1 with SCR)
IMPORTANT:
Read and comply with notes on protection against electrostatic damage ESD protection).
Necessary preliminary tasks:
- Read out the fault memory of the DDE control unit.
- Switch off ignition.
- Disconnect BATTERY NEGATIVE LEAD .
- Remove ACOUSTIC COVER
- Remove FRONT, REAR ACOUSTIC COVER AND SOUND INSULATION on injectors.
- Remove front UNDERBODY PROTECTION .
- Remove ELECTRONICS BOX .
Pull out fasteners (1) in direction of arrow.
Push back sockets (2) and detach engine wiring harness from connector housing.
Release screw (1).
Release cable channel (2).
| 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 from all electric changeover valves and pull off | |
| Unlock connector on exhaust backpressure sensor and fuel differential-pressure sensor and pull off | |
| Unfasten connectors from exhaust temperature sensors and disconnect | |
| 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 | |
| Release nut (1) on starter motor, detach cable (terminal 50) | |
| Unlock connector on transmission 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 | |
| Release and unplug connector from preheating control unit | |
| Unfasten electrical connector from SCR metering unit and disconnect | |
| Unfasten electrical connector from control unit for nitrogen oxide sensor upstream of NOx catalytic converter and disconnect | |
| Unlock connector on monitoring sensor and disconnect |
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.