PACCAR MX (2004 Emissions) Fault Code: U1847 PCI ECU Software Verification – Incorrect

PACCAR MX (2004 Emissions) Fault Code: U1847 PCI ECU Software Verification – Incorrect

SET CONDITIONS:
The PCI ECU detects that the calibration verification number (CVN) is incorrect.

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

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
This DTC changes to inactive next time the ignition is keyed on 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? (Can be pending, inactive or active)
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
Reprogram the ECU with correct software.

ADDITIONAL INFORMATION:
When the ignition is keyed on, the PCI ECU (D420) checks if the correct calibration verification number (CVN) is detected.

CVN is the calibration verification number and is the result of a check performed on the software values stored in emission-related ECUs (OBD legislation).