CAN Message N_MOT Invalid (Flag F_N_MOT)

DTC P1884
CAN Message N_MOT invalid (flag F_N_MOT).

Possible causes:
^ Engine speed measurement fault present in engine management ECM.

Engine Speed Measurement Fault Present In Engine Management ECM.
CHECK THE FOLLOWING:
^ Read ECM fault codes and diagnose any faults likely to cause problems with engine speed measurement (e.g. Crankshaft sensor, reference position).
POSSIBLE FAULTS
^ Fault codes set in engine management ECM.