Computer/Controls - Proper Engine Harness Installation, Grounds
SI B12 18 12
Engine Electrical Systems
November 2012
Technical Service
SUBJECT
N63: Proper Engine Harness Installation and Ground Connections
MODEL
All with N63
SITUATION
There are BSD communication fault(s) set shortly after repairs requiring the removal of the ignition harness from the cylinder head cover. Diagnosis
of the fault leads to isolating the damaged component on the BSD circuit (DME, alternator, QLT sensor).
2010 BMW 750i xDrive AWD (F01) V8-4.4L Turbo (N63) Page 3
Depending on the type of fault, when BSD communication is disrupted and oil level sensor (QLT) data is no longer received by the DME, possible
symptoms will include: a reduced CBS oil service forecast, inability to reset the CBS oil service, and oil level measurement not possible.
A BSD component may become damaged immediately upon engine operation if the ground circuit, integrated into the metal bushing of the ignition
coil harness duct on either cylinder bank, is not properly secured to the engine cover with the correct bolt and to the specified torque.
This ground point location is shown in the pictures below.
It is absolutely essential that during any engine repairs which require loosening or removing of the harness, special attention must be paid during
reassembly to ensure these ignition coil harness bolts be the correct part and tightened to the specified torque before attempting to start the engine.
