PACCAR MX (2004 Emissions) Fault Code: U1571 EGR Valve Module – CAN, Message Time-Out

PACCAR MX (2004 Emissions) Fault Code: U1571 EGR Valve Module – CAN, Message Time-Out

SET CONDITIONS:
The PCI ECU (D420) lost communication with the EGR valve module (L095).

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. EGR valve module power supply
2. E-CAN communication
3. Faulty EGR valve module

ADDITIONAL INFORMATION:
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.