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Home >> BMW >> 2012 >> 335is 2D Coupe >> Repair and Diagnosis >> Engine Performance >> Tune-Up >> Engine Electrical System - Repair - E92 >> Engine Wiring Loom >> 12 51 001 Replacing wiring harness section for engine (N54, N54T)

12 51 001 Replacing wiring harness section for engine (N54, N54T)

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

Necessary preliminary tasks: 

Unlock fasteners (1) from below and slide upwards approx. 10 mm.

Unlock locks (2) in direction of arrow.

Remove cover (3).

Fig 1: Removing Cover Fasteners
G09846578Courtesy of BMW OF NORTH AMERICA, INC.

Unlock connector (1) and remove.

Release grommet (2) from electronics box.

Installation note: 

Make sure grommet (2) is correctly seated in housing.

(watertightness).

Raise control unit (3) slightly.

Fig 2: Identifying Control Unit, Connector And Grommet
G09846579Courtesy of BMW OF NORTH AMERICA, INC.

Unlock connectors (1) using slide in direction of arrow and remove.

Fig 3: Removing Connectors
G09846580Courtesy of BMW OF NORTH AMERICA, INC.

Short connector:

Unlock slide (2) in bore holes (1) and pull out of housing.

Unlock tab (3), pull contact carrier (4) in direction of arrow out of housing.

Fig 4: Pulling Contact Carrier
G04751359Courtesy of BMW OF NORTH AMERICA, INC.

Long connector:

Press locking tab (1) in direction of arrow and pull contact carrier (2) out of housing.

Unlock and disconnect all plug connections of engine wiring harness section in electronics box.

Fig 5: Pulling Contact Carrier
G04755175Courtesy of BMW OF NORTH AMERICA, INC.
Work step
Unlock plug connections on control sensors and disconnect
Unlock connector on heating pipe and disconnect
Unlock connector on alternator and disconnect
Unlock plug connection on knock sensors and disconnect
Release connector on crankshaft sensor and disconnect
Unlock connector on starter motor and disconnect
Unlock connector on high pressure pump and disconnect
Unlock connector on low pressure sensor and disconnect
Unlock connector on air conditioning compressor and disconnect
Remove REAR UNDERBODY PROTECTION
Unlock plug connections on monitoring sensors and disconnect
Unlock connector on oil condition sensor and disconnect
NOTE: Check stored fault messages.

Delete fault memory.