BMW E38 crankshaft and camshaft sensor fault
What symptoms does a crankshaft or camshaft sensor fault cause in an E38?
The engine runs badly or stalls, power is lost and the car jerks. A crankshaft sensor fault feels like misfiring in steady driving, and a camshaft sensor fault like jerking under acceleration. The automatic gearbox can go into limp mode. The sensor can be faulty even without a fault code.
How can the sensor be checked?
In addition to fault codes, look at the engine management live data: if the engine speed shows zero, the crankshaft sensor is suspect. A resistance measurement only tells whether the wire is broken, because the crankshaft sensor is inductive and its operation is checked with an oscilloscope.
Is it worth buying a cheap aftermarket sensor for an E38?
No. An aftermarket sensor may not give the engine management a signal, and the original sensor fixed the symptoms. The E34's sensor also does not appear to fit. The sensors are sensitive to impact, and a small dent at the tip of the sensor or dirt on it can cause a fault.
What if the fault code stays after the sensor has been replaced?
The fault may be elsewhere: the engine's timing may be off, in which case the code does not blame the sensor. Have a workshop check the situation if replacing the sensor does not help. The condition and mounting of the crankshaft damper should also be checked.