Engine position (camshaft) sensor abnormal signal
The signal is there but the timing of it is wrong — wrong pulse rate, wrong duty cycle, wrong spacing.
SPN 636 — Engine position (camshaft) sensor abnormal signal
SPN 636 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.
Engine position (camshaft) sensor abnormal signal
The signal is there but the timing of it is wrong — wrong pulse rate, wrong duty cycle, wrong spacing.
Engine position (camshaft) sensor abnormal signal
The signal is there but the timing of it is wrong — wrong pulse rate, wrong duty cycle, wrong spacing.
Engine position (camshaft) sensor abnormal signal
The signal is there but the timing of it is wrong — wrong pulse rate, wrong duty cycle, wrong spacing.
Engine position (camshaft) sensor abnormal signal
The signal is there but the timing of it is wrong — wrong pulse rate, wrong duty cycle, wrong spacing.
Engine position (camshaft) sensor abnormal signal
The signal is there but the timing of it is wrong — wrong pulse rate, wrong duty cycle, wrong spacing.
Engine position (camshaft) sensor abnormal signal
The signal is there but the timing of it is wrong — wrong pulse rate, wrong duty cycle, wrong spacing.
Engine position (camshaft) sensor abnormal signal
The signal is there but the timing of it is wrong — wrong pulse rate, wrong duty cycle, wrong spacing.
The reference is free. The diagnosis is Pro.
Every SPN and FMI page on this site stays open — no account needed. Pro members can take the code into Truck Commander Pro AI with the VIN, symptoms and photos, keep per-truck history, and print a work order. $14.99 a month or $99.99 a year.