1251100 Replacing wiring harness section for ignition coil (N52K, N51)

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2011 BMW 328xi, 2011 BMW 328i, 2010 BMW 328xi, 2010 BMW 328i, and 2009 BMW 328xi. However, it is still accessible from the selected car via links, so may be relevant.

IMPORTANT: Aluminium-magnesium materials.
No steel screws/bolts may be used due to the threat of electrochemical corrosion.
A magnesium crankcase requires aluminium screws/bolts exclusively.
Aluminium screws/bolts must be replaced each time they are released.
Aluminium screws/bolts are permitted with and without color coding (blue).
For reliable identification:
Aluminium screws/bolts are not magnetic.
Jointing torque and angle of rotation must be observed without fail (risk of damage).

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

Necessary preliminary tasks:

Read out fault memory of DME control unit
Switch off ignition
Disconnect BATTERY NEGATIVE LEAD
Remove IGNITION COIL COVER
Remove INTAKE DUCT

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

Unlock locks (2) in direction of arrow.

Remove cover (3).

Fig 1: Opening Locks

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Unlock plug (1) and remove.

Unlock control unit (2) and raise approx. 5 cm.

Release grommet (3) from electronics box.

Installation:

Make sure grommet (3) is correctly seated in electronics box (watertightness).

Fig 2: Identifying Plug And Control Unit

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Unlock tab (1). Pull contact carrier (2) in direction of arrow out of housing.

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

Fig 3: Pressing Locking Tab

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

Fig 4: Pressing Locking Tab

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

Fig 5: Pressing Locking Tab

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WORKING STEPS - REPLACING WIRING HARNESS

Work step	Note:
Disconnect positive lead from battery positive terminal
Disconnect ground cables
Unlock plug connections on ignition coils and disconnect
Unlock cable duct on cylinder head cover and detach
Unlock plug on eccentric shaft sensor and disconnect
Unlock plug on positioning motor for eccentric shaft and disconnect
Unlock plug on both solenoid valves and disconnect
Unlock plug on inlet and exhaust camshaft sensors and disconnect
Unlock plug on air-conditioning compressor and disconnect
Unlock plug on oil pressure switch and disconnect
Unlock plug on coolant temperature sensor and disconnect
Disconnect connector strip from fuel rail
Remove front UNDERBODY PROTECTION
Unlock plug on electric coolant pump and disconnect
Unlock plug on coolant thermostat and disconnect
Disconnect engine ground connection	Tightening torque 12 52 3AZ . Replace screw.

NOTE: Check stored fault messages.
Now clear the fault memory.