Cummins ISM CM875 (2003-06) Fault Code: 731 PID: S064 SPN: 723 FMI: 7/7 Engine Speed Sensor and Camshaft Position Sensor – Mechanical Misalignment Between Camshaft and Crankshaft Sensors. Engine position signal from the engine speed sensor and camshaft position sensor do not match.

Possible causes:

1)Loose, missing, or corroded grounds
2)Damaged tone wheel teeth
3)Loose crankshaft tone wheel
4)Static timing misset
5)Front gear train slippage
6)Misoriented engine speed or camshaft position sensor
7)Electrical noise.

Possible repairs:

1)Replace the speed or position sensor.
2)Replace the crankshaft or injector camshaft, whichever has malfunctioned.