Cummins ISB4.5 CM2150 Fault Code: 778 PID: SPN: 723 FMI: 2 Engine Camshaft Speed/Position Sensor – Data Erratic, Intermittent, or Incorrect.

Circuit Description
The engine control module (ECM) provides 5 volt supply to the engine camshaft speed/position sensor on the sensor supply circuit. The ECM also provides a ground on the sensor return circuit. The camshaft speed/position sensor provides a signal to the ECM on the camshaft speed/position sensor signal circuit. This sensor generates a signal to the ECM as the camshaft speed indicator lobe moves past the sensor. The ECM interprets this signal into an engine speed reading and determines engine position. This sensor is used as a backup sensor if the primary engine crankshaft speed/position signal is lost.

Conditions for Running the Diagnostics
This diagnostic runs continuously when the engine is running.

Conditions for Setting the Fault Codes
The ECM detects a loss of the camshaft speed/position sensor for more than 1 second.

Action Taken When the Fault Code is Active
The ECM illuminates the amber CHECK ENGINE light and/or the malfunction indicator lamp (MIL) immediately when the diagnostic runs and fails.

Conditions for Clearing the Fault Code
-To validate the repair, start the engine and let it idle for 1 minute.
-The ECM will turn off the amber CHECK ENGINE light immediately after the ECM detects a valid signal from the crankshaft speed/position sensor.
-The ECM will turn off the MIL after three consecutive ignition cycles that the diagnostic runs and passes.
-This fault code and MIL can also be cleared with INSITE™ electronic service tool.

Possible Causes
-Open or short circuit of the 5 volt supply, signal, or return wire in the engine harness
-Damaged or malfunctioning camshaft position sensor.