Cummins ISX CM870 (2003-06) Fault Code: 2376 PID: P412 SPN: 412 FMI: 4/4 Recirculated Exhaust Gas Temperature Sensor Circuit – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at EGR temperature circuit.

Beginning with ESN 14039654, the temperature sensor return circuit was separated from the pressure sensor return circuit. For ESNs prior to this and with engine wiring harness Part Number 3682854, refer to the Common Pressure/Temperature Sensor Return Circuit above. For this ESN and greater or for any other engine wiring harness part number, refer to the Separate Pressure/Temperature Sensor Return Circuit above.

This fault code is set active if the sensor signal voltage is below the normal operating range for the sensor and the ECM has commanded the EGR valve open. This fault code will not be set active if the ECM has commanded the EGR valve closed. However, once the fault code is set, it will remain active independent of whether the EGR valve is open or closed.

The EGR temperature sensor shares return wires in the engine harness with other sensors. A shorted return can cause multiple fault codes to be active. Before troubleshooting Fault Code 2376, check for multiple fault codes.

Possible causes:

1)Signal shorted to ground in the harness or ECM
2)Signal shorted to return or ground in the sensor.

Possible repairs:

1)Replace the EGR temperature sensor.
2)Replace the ECM.
3)Repair or replace the engine harness.