N63: Proper Ignition Harness Installation and Ground Connections

BMW TSB #SI B12 24 14, Engine Electrical Systems, September 2014 Technical Service.

MODEL All with the N63 engine SITUATION The BSD (Bit Serial Data) interface communication fault(s) are set shortly after repairs, which required removal of the ignition harness from the cylinder head cover. Depending on the type of a fault, when the BSD communication is disrupted and the oil level sensor (QLT) data is no longer received by the DME, possible symptoms will include:  Reduced CBS oil service forecast  Not possible to reset the CBS oil service  Oil level measurement not possible Diagnosis of the fault leads to isolating the damaged component on the BSD circuit (DME, alternator voltage regulator, QLT sensor). CAUSE Any of the BSD interface components could be damaged immediately upon engine start if the ignition ground circuit, integrated into the metal bushing of the ignition coil harness duct on both cylinder banks, is not secured to the engine cover with the correct bolt and to the specified torque.

Courtesy of https://static.nhtsa.gov/odi/tsbs/2014/MC-10148021-9999.pdf