12 51 100 Replacing Wiring Harness Section For Ignition Coil (N52)

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IMPORTANT:

Aluminum-magnesium materials.

No steel screws/bolts may be used due to the threat of electrochemical corrosion.

A magnesium crankcase requires aluminum screws/bolts exclusively.

Aluminum screws/bolts must be replaced each time they are released.

Aluminum screws/bolts are permitted with and without color coding (blue).

For reliable identification:

Aluminum 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). See 61 35... NOTES ON ESD PROTECTION (ELECTRO STATIC DISCHARGE) (CONVERTIBLE) or 61 35... NOTES ON ESD PROTECTION (ELECTRO STATIC DISCHARGE) (COUPE) .

Necessary preliminary tasks:

Read out fault memory of DME control unit
Switch off ignition
Follow instructions for disconnecting and connecting battery . See 12 00... Instructions For Disconnecting And Connecting Battery .
Disconnect battery negative lead from battery and lay to one side
Remove lower section of microfilter housing . See 64 31 081 REMOVING AND INSTALLING/REPLACING MICROFILTER HOUSING (UPPER SECTION) and 64 31 092 REMOVING AND INSTALLING/REPLACING MICROFILTER HOUSING (LOWER SECTION)
Remove acoustic cover . See 11 00 REMOVING AND INSTALLING/REPLACING ACOUSTIC COVER (N52/N52K) .
Remove cylinder head cover . See 11 12 000 REMOVING AND INSTALLING OR SEALING CYLINDER HEAD COVER (N52K) .

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

Unlock locks (2) in direction of arrow.

Remove cover (3).

Fig 1: Unlocking Locks In Direction Of Arrow

Courtesy of BMW OF NORTH AMERICA, INC.

Unlock plug (1) and remove.

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

Fig 2: Unlock Plug & Control Unit

Courtesy of BMW OF NORTH AMERICA, INC.

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: Pulling Contact Carrier

Courtesy of BMW OF NORTH AMERICA, INC.

Illustration shows cylinder head cover.

Release screws and remove holder (1).

Tightening torque, see 12 52 1AZ in 12 52 PLUG CONNECTIONS, TERMINALS, LOOSE PARTS .

Fig 4: Locating Holder & Screws

Courtesy of BMW OF NORTH AMERICA, INC.

Release screws and remove cable duct (1).

Installation:

Replace aluminum screws.

Tightening torque, see 12 52 2AZ in 12 52 PLUG CONNECTIONS, TERMINALS, LOOSE PARTS .

Fig 5: Locating Cable Duct & Screws

Courtesy of BMW OF NORTH AMERICA, INC.

WORK STEP TABLE

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 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, see 12 52 3AZ in 12 52 PLUG CONNECTIONS, TERMINALS, LOOSE PARTS . Replace screw.

NOTE:

Check stored fault messages.

Now clear the fault memory.