PACCAR PX-9 CM2350 (2013-17) Fault Code:1867 PID:412 SPN:412 FMI:2 Exhaust Gas Recirculation Temperature – Data Erratic, Intermittent, or Incorrect

Reason:
Engine Gas Recircuilation Temperature – Data Erratic, Intermittent, or Incorrect. Engine misfire has been detected in multiple cylinder numbers.

Effect:
Possible reduced engine performance

Circuit Description:
The exhaust gas recirculation (EGR) temperature sensor is a variable resistor sensor and is used to measure the temperature of the EGR gas flow after it exits the EGR cooler. The engine control module (ECM) supplies 5 volts to the EGR temperature signal circuit. The ECM monitors the change in voltage caused by changes in the resistance of the sensor to determine the EGR flow temperature.

The EGR temperature value is used by the ECM for the engine protection system and engine emissions control.

Component Location:
The EGR temperature sensor is located on the EGR connection tube between the EGR cooler and the air intake connection.

Conditions for Running the Diagnostics:
This diagnostic consists of two parts. The first part runs when the keyswitch is turned to the ON position after a 8 hour cold soak, during which the keyswitch has been turned OFF. The second part runs continuously while the engine is running and EGR flow is above a calibratible value.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected the EGR temperature reading was too high or tool low for the operating conditions, or the EGR temperature reading was not changing with the operating conditions.

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) Diesel exhaust fluid injection into the aftertreatment system is disabled.
3) Active and stationary regeneration of the diesel particulate filter will be disabled.
4) Exhaust Gas Recirculation (EGR) valve operation will be disabled.
5) 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, start the engine and let it idle for 1 minute. The vehicle may also need to be driven in order to meet EGR flow requirements so that the diagnostic can run.
2) If the fault code does not go inactive, it may be necessary to perform a 8 hour cold soak with the key OFF, then turn the keyswitch to the ON position so that the key ON portion of the diagnostic will run.
3) The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
4) The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
5) 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.
6) 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:
N/A

Possible Causes:
1) Stuck in-range EGR temperature sensor
2) High resistance in the EGR temperature sensor signal or return wires