Cummins ISL CM850 (2003-06) Fault Code: 778 PID: SID 64 SPN: 723 FMI: 2 Engine Speed Sensor (Camshaft) Error – Data Erratic, Intermittent, or Incorrect. The ECM has detected an error in the camshaft position sensor signal.

Cummins ISL CM850 (2003-06) Fault Code: 778 PID: SID 64 SPN: 723 FMI: 2 Engine Speed Sensor (Camshaft) Error – Data Erratic, Intermittent, or Incorrect. The ECM has detected an error in the camshaft position sensor signal.

This fault is recorded when the ECM does not receive a signal from the camshaft position sensor or the signal the ECM receives is degraded.

Possible causes:

1)Open circuit on the supply, signal, or return circuits in the sensor, engine harness, or ECM
2)Short circuits to ground or return circuits in the sensor, engine harness, or ECM
3)Short circuits to voltage source in the sensor, engine harness, or ECM.

INSITE? electronic service tool monitor parameters associated with this fault code and sensor include:

1)Camshaft engine position sensor state
2)Damage to the sensor target teeth or tone wheel.

If this fault code occurs intermittently, look closely for causes of intermittent harness connections such as loose or worn pins in the engine harness connectors.

If this fault code occurs intermittently, Fault Code 2322 will also be active or have high counts.

Possible repairs:

1)Replace the camshaft engine position sensor.
2)Replace or shim the sensor if the air gap is out of specification.
3)Repair or replace the engine harness.
4)Replace the ECM.