PACCAR MX (2004 Emissions) Fault Code: U1573 EGR Valve Module Position – Data Erratic, Intermittent, or Incorrect

SET CONDITIONS:
The PCI ECU (D420) receives a CAN message from the EGR valve module (L095) that contains an out-of-range value for the actuator shaft position.

DIAGNOSTIC CONDITION:
This diagnostic runs continuously when the ignition is on.

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
This DTC changes to inactive after the ignition is keyed off for at least 15 seconds and keyed on again, and the fault is no longer detected.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back?
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
1. This DTC can be a result of an EGR valve module-related P-code. Troubleshooting these P-codes first.
2. E-CAN communication
3. Faulty EGR valve module

ADDITIONAL INFORMATION:
1. The EGR valve actuator is a smart actuator that communicates with the PCI ECU via E-CAN. The actuator ECU is controlled by the PCI ECU but has its own diagnostics.
2. The position of the actuator shaft, and therefore, the position of the EGR valve is monitored.