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Home >> BMW >> 2016 >> 550i >> Repair and Diagnosis >> Engine Performance >> Tune-Up >> Engine Electrical System - Repair >> Engine Wiring Loom >> 12 51 306 Removing and installing/replacing supply module wiring harness section (N63 B40/44 O 1)

12 51 306 Removing and installing/replacing supply module wiring harness section (N63 B40/44 O 1)

IMPORTANT: Read and comply with notes on PROTECTION AGAINST ELECTROSTATIC DISCHARGE (ESD PROTECTION) .
IMPORTANT: Screw back on all screw points of cable channels without fail!  Some screw points are also ground points  . If the wiring harnesses are not correctly screwed tight and secured, this may cause DME malfunction and failure!

Necessary preliminary tasks: 

Overview of supply module wiring harness section.

Picture shows the left side, the procedure for the right side is identical.

Slacken nut (1).

Tightening torque 12 51 2AZ .

Remove ground cable.

IMPORTANT: If the nut (1) is released, the ground pin (double pin) underneath must  be retightened!

Retighten ground pin.

Tightening torque 12 51 3AZ .

Fig 2: Identifying Slacken Nut Of Ground Cable
G09875474Courtesy of BMW OF NORTH AMERICA, INC.

Release screws (1).

Release clamp (2).

Remove lid (3) from auxiliary box.

Fig 3: Identifying Cover, Clamp And Screws
G06888952Courtesy of BMW OF NORTH AMERICA, INC.

Disconnect all plugs from carrier plate (1) and release from supplementary electronics box.

Installation note: 

Make sure rubber grommets are correctly fitted (watertightness).

Fig 4: Identifying Plugs From Carrier Plate
G09914329Courtesy of BMW OF NORTH AMERICA, INC.

Release screw (1).

Tightening torque 17 22 4AZ .

Release screw (2).

Tightening torque 17 22 5AZ .

Remove engine oil pipes from oil filter control housing and take off oil sump.

Catch and dispose of emerging oil.

Installation note: 

Replace all sealing rings of engine oil pipes!

Check the engine oil level after repair work is completed. Top up, if applicable.

Fig 5: Identifying Engine Oil Pipes Mounting Screws
G06889287Courtesy of BMW OF NORTH AMERICA, INC.
Unlock and disconnect following connectors and lines
Unlock connector on transmission and disconnect
Unlock connector of DME control units and pull off
Unlock plug connection to wiring harness section sensor system module cylinder 1-4 (in vicinity of starter motor) and pull off.

Release wiring harness if necessary from existing clips and clamps.

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.