P0373: The crankshaft reference position becomes erratic

BMW's N62TU chart links P0373 to fault 2B5D and an erratic crankshaft reference. The defining memory criterion is a reference-point position that shifts by one tooth at least nine times. This is different evidence from a sensor that never produces a signal.

Why an RPM reading can remain plausible

A timing reference can move inconsistently even when enough pulses remain for a displayed engine speed. A normal-looking RPM value alone therefore cannot verify this diagnostic. The important issue is whether the reference event occurs at the expected position in the tooth pattern.

The monitor requires the engine to be turning and Terminal 15 active. BMW's service direction covers the connector and harness as well as sensor-to-reluctor geometry, with sensor replacement considered after those checks. The physical target and electrical signal path are both relevant to an apparent positional shift.

Avoid confusing fallback behavior with a separate failure

The chart lists valve-lift and VANOS emergency strategies, but explicitly indicates that the RPM-sensor emergency mode is not active for this entry. This differs from the related missing-reference chart and helps explain why the vehicle can retain some speed information despite a timing-reference fault.

The emissions lamp is listed for the second driving cycle. Verification should focus on repeatable reference position and the integrity of the sensing arrangement, rather than waiting only for a lamp to extinguish. This explanation does not assign a particular damaged tooth or connector fault: the code establishes the observed pattern, while the matching workshop tests establish its cause.

Source and applicability

BMW diagnostic chart, P0373. 2008 BMW 750Li (E66), N62TU 4.8L; BMW DME monitor chart reproduced by Operation CHARM. These values describe that documented monitor; they are not universal specifications for every vehicle displaying this code.