Cummins ISX CM870 (2003-06) Fault Code: 778 PID: S64 SPN: 723 FMI: 2/2 Engine Camshaft Speed / Position Sensor – Data Erratic, Intermittent, or Incorrect.? The ECM has detected a loss of signal from the camshaft position sensor.

This fault is logged when the ECM does not receive a valid camshaft position signal.

Possible repairs:

1)Open or short circuit of the +5 volt supply, signal, or return wire in the engine harness
2)Damaged or failed camshaft position sensor.

Possible repairs:

1)Replace the engine wiring harness.
2)Replace the camshaft position sensor.
3)Inspect the camshaft tone wheel/gear teeth for damage or spinning.
4)Replace the ECM.