12 51 100 Replacing wiring harness section for ignition coil (N52)

WARNING: This page does not describe the selected car, but rather 14 other vehicles, including the 2008 BMW Z4, 2008 BMW 328xi, 2008 BMW 328i, 2008 BMW 323i, and 2007 BMW Z4. 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.

The end faces of aluminium screws/bolts are painted blue for the purposes of reliable identification.

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
Follow Instructions For Disconnecting And Connecting Battery
Disconnect Battery Negative Lead from battery and lay to one side
Remove Lower Section Of Microfilter Housing
Remove Acoustic Cover
Remove Cylinder Head Cover

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

Unlock locks (2) in direction of arrow.

Remove cover (3).

Fig 1: Identifying Wiring Harness Cover, Fasteners And Locks

Courtesy of BMW OF NORTH AMERICA, INC.

Unlock plug (1) and remove.

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

Fig 2: Identifying Plug And Control Unit

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Unlock plug on control unit and disconnect.

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: Identifying Control Unit Tab And Contact Carrier

Courtesy of BMW OF NORTH AMERICA, INC.

Illustration shows cylinder head cover.

Release screws and remove holder (1).

For tightening torque refer to 12 52 1AZ in 12 52 PLUG CONNECTIONS, TERMINALS, LOOSE PARTS .

Fig 4: Identifying Cylinder Head Cover Holder And Screws

Courtesy of BMW OF NORTH AMERICA, INC.

Release screws and remove cable duct (1).

Installation:

Replace aluminium screws.

For tightening torque refer to 12 52 2AZ in 12 52 PLUG CONNECTIONS, TERMINALS, LOOSE PARTS .

Fig 5: Identifying Cable Duct With Screws

Courtesy of BMW OF NORTH AMERICA, INC.

WORK STEP CHART

Work step	Note:
Unlock plug connections on ignition coils and disconnect
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 A/C compressor and disconnect
Unlock plug on oil pressure switch and disconnect
Unlock plug on coolant temperature sensor and disconnect
Disconnect connector strip from injection pipe
Remove Front Underbody Protection
Unlock plug on electric coolant pump and disconnect
Unlock plug on coolant thermostat and disconnect
Disconnect engine ground connection	Replace screw. For tightening torque refer to 12 52 3AZ in 12 52 PLUG CONNECTIONS, TERMINALS, LOOSE PARTS .

NOTE: Check stored fault messages.

Now clear the fault memory.