PACCAR MX (2004 Emissions) Fault Code: U1408 VTG Turbocharger Actuator Status – Data Erratic, Intermittent or Incorrect

Description

SET CONDITIONS:
The PCI ECU (D420) receives a CAN message from the VTG turbocharger actuator (L037) that contains an out-of-range value for the actuator status.

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 a VTG turbo charger actuator-related P-code. Troubleshooting these P-codes first.
2. Communication error between actuator and PCI ECU
3. Faulty VTG turbocharger actuator

ADDITIONAL INFORMATION:
The VTG turbocharger is controlled by the VTG turbocharger actuator, 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.