Cummins ISX CM870 (2003-06) Fault Code: 2374 PID: P95 SPN: 1029 FMI: 4/4 Exhaust Gas Pressure Sensor Circuit – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the exhaust gas pressure circuit.

The exhaust gas pressure sensor shares supply and return wires in the engine harness with other sensors. Opens and shorts in the engine harness can cause multiple fault codes to be active.
Possible causes:

1)A signal circuit open or shorted to ground in the engine harness or sensor
2)A supply wire open or shorted to ground.

Possible repairs:

1)Replace the exhaust gas pressure sensor.
2)Replace the ECM.
3)Repair or replace the engine harness