PACCAR PX-9 CM2350 (2013-17) Fault Code:2374 PID:131 SPN:1209 FMI:4 Exhaust Gas Pressure Sensor 1 Circuit – Voltage Below Normal or Shorted to Low Source

Reason:
Exhaust Gas Pressure Sensor Circuit – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the exhaust gas pressure circuit.

Effect:
Possible reduced engine performance.

Circuit Description:
The exhaust gas pressure sensor is used to measure exhaust gas pressure in the exhaust manifold. This information is used by the engine control module (ECM) to control emissions and exhaust gas recirculation (EGR) valve operation. The ECM provides a 5 volt supply to the exhaust gas pressure sensor on the sensor supply circuit. The ECM also provides a ground on the sensor return circuit. The exhaust gas pressure sensor provides a signal to the ECM on the exhaust gas pressure sensor signal circuit. This sensor signal voltage changes, based on the pressure in the exhaust manifold.

Component Location:
The exhaust gas pressure sensor is located above the front section of the exhaust manifold and is plumbed into the exhaust manifold.

Conditions for Running the Diagnostics:
This diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected the exhaust gas pressure signal voltage was less than 0.25-VDC for more than 8 seconds.

Action Taken When the Fault Code is Active:
1) The ECM illuminates the amber CHECK ENGINE lamp and/or the Malfunction Indicator Lamp (MIL) immediately when the diagnostic runs and fails.
2) A default value is used for the exhaust gas pressure sensor reading.
3) Diesel exhaust fluid injection into the aftertreatment system is disabled.
4) Active and stationary regeneration of the diesel particulate filter will be disabled.
5) Exhaust Gas Recirculation (EGR) valve operation will be disabled.
6) Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.

Conditions for Clearing the Fault Code:
1) To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
2) The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
3) The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
4) For On-Board Diagnostics (OBD) engines, the ECM will extinguish the Malfunction Indicator Lamp (MIL) after three consecutive trips where the diagnostic runs and passes.
5) The Reset All Faults command in INSITE™ electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk:
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