Crankshaft position sensor abnormal signal
The signal is there but the timing of it is wrong — wrong pulse rate, wrong duty cycle, wrong spacing.
SPN 637 — Crankshaft position sensor abnormal signal
SPN 637 is the parameter the ECM is flagging on CAT, Detroit, International, PACCAR, MERCEDES, Volvo, Mack, Cummins engines. The FMI that comes with it tells you how it failed. Each failure mode below has its own causes and its own test order — do not treat them as the same repair.
Crankshaft position sensor abnormal signal
The signal is there but the timing of it is wrong — wrong pulse rate, wrong duty cycle, wrong spacing.
Crankshaft position sensor abnormal signal
The signal is there but the timing of it is wrong — wrong pulse rate, wrong duty cycle, wrong spacing.
Crankshaft position sensor abnormal signal
The signal is there but the timing of it is wrong — wrong pulse rate, wrong duty cycle, wrong spacing.
Crankshaft position sensor abnormal signal
The signal is there but the timing of it is wrong — wrong pulse rate, wrong duty cycle, wrong spacing.
Crankshaft position sensor abnormal signal
The signal is there but the timing of it is wrong — wrong pulse rate, wrong duty cycle, wrong spacing.
Crankshaft position sensor abnormal signal
The signal is there but the timing of it is wrong — wrong pulse rate, wrong duty cycle, wrong spacing.
Crankshaft position sensor abnormal signal
The signal is there but the timing of it is wrong — wrong pulse rate, wrong duty cycle, wrong spacing.
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