12 51 001 Replacing wiring harness section for engine (N54)
Aluminium screws/bolts are permitted with and without color coding (blue).
For reliable identification:
Jointing torque and angle of rotation must be observed without fail (risk of damage) .
Necessary preliminary tasks:
- Read out fault memory of DME control unit
- Turn off ignition
- Disconnect BATTERY NEGATIVE LEAD
- Remove right SUSPENSION CROSS-BRACE
- Remove ACOUSTIC INSULATION for bulkhead on left
- Remove INTAKE AIR MANIFOLD
- Remove WIRING HARNESS for injectors and ignition coils
- Remove FAN COWL
- Remove FRONT UNDERBODY PROTECTION
- Remove REAR UNDERBODY PROTECTION
Picture shows the left side, the procedure for the right side is identical
Lever expander rivets (1) out of cover (2).
Installation:
If necessary, replace damaged expander rivets.
Make sure holders (3) are correctly seated.
Release screws (1).
Tightening torque 12 90 4AZ .
Release clip (2).
Remove cover (3) from supplementary box.
Disconnect all plugs from carrier plate (1) and release from supplementary electronics box.
Installation:
Make sure rubber grommets are correctly seated (watertightness).
Unclip grommet hold-down device (1).
Release wiring harnesses (2) from bulkhead.
Release screws (1).
Tightening torque 12 90 2AZ .
Remove electronics box cover (2).
Unlock all plugs (1) from control unit and disconnect.
Unclip grommet hold-down device (2) and remove.
Release rubber grommets (3) from electronics box. Lay wiring harnesses to one side.
Installation:
Make sure grommets are correctly seated (watertightness).
Slacken nut (1).
Tightening torque 12 51 1AZ .
Detach ground cable (2).
Release screws (1).
Tightening torque 12 51 2AZ .
Detach cable duct.
Release screws (1).
Tightening torque 11 12 8AZ .
Remove metal bracket (2).
Release screws (1).
Tightening torque 13 62 6AZ .
Release cable duct (2).
| Unlock and disconnect following plugs and leads |
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| Unlock both plugs on oxygen sensors and disconnect |
| Unlock plug on transmission and disconnect |
| Unlock plug on both pressure converters and disconnect |
| Unlock plug on both camshaft control solenoid valves and disconnect |
| Unlock plug on coolant temperature sensor and disconnect |
| Unlock plug on inlet camshaft pulse sensor and disconnect |
| Unlock plug on exhaust camshaft pulse sensor and disconnect |
| Unlock plug on oil pressure sensor and disconnect |
| Unlock plug on oil level sensor and disconnect |
| Unlock plug on tank vent valve and disconnect |
| Unlock plug on both monitoring sensors and disconnect |
| Unlock plug on crankshaft sensor and disconnect |
| Unlock plug on throttle valve assembly and disconnect |
| Unlock plug on heating element for air duct and disconnect |
| Unlock plug on high-pressure fuel sensor and disconnect |
| Unlock plug on intake air pressure sensor and disconnect |
| Unlock plug on intake air temperature sensor and disconnect |
| Unlock plug on A/C compressor and disconnect |
| Unlock plug on changeover valve and disconnect |
| Unlock plug on alternator and disconnect |
| Unlock plug on knock sensors and disconnect |
| Unlock plug on low-pressure fuel sensor and disconnect |
| Unlock plug on starter and disconnect |
| Unlock plug on high-pressure pump and disconnect |
| Unlock plug on coolant thermostat and disconnect |
| Unlock plug on coolant pump and disconnect |
Release wiring harness from clips and retainers.
Feed out wiring harness and remove.
Installation:
Check wiring harness routing.
Check plug connections for correct seating.
Check stored fault message.
clear fault memory.