PACCAR MX (2004 Emissions) Fault Code: U142F CAN Communication – Message (ACM_to_Eng) Out of Range, Estimated Pre-DOC Pressure from Aftertreatment System

SET CONDITIONS:
This DTC is set when the CAN message containing the calculated pressure before the DOC is not received correctly.

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

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
The DTC changes to inactive after the diagnostic runs and passes.

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. PCI ECU software bug
2. A corrupt or empty CAN message

ADDITIONAL INFORMATION:
This DTC does not activate a warning on the vehicle display.

IMPORTANT: In exceptional cases this DTC can be triggered inadvertently at the moment the ignition is keyed off. If no related DTCs are active, do not troubleshoot this DTC.