PACCAR MX (2004 Emissions) Fault Code: P109D Common Rail Pressure Release Valve – Current Too High on ECU (D420) Pin (C4)

PACCAR MX (2004 Emissions) Fault Code: P109D Common Rail Pressure Release Valve – Current Too High on ECU (D420) Pin (C4)

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

CORRESPONDING OBD READINESS MONITOR:
None

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

ADDITIONAL INFORMATION:
When this DTC is active:
1. The engine torque is reduced.
2. The engine runs in protection mode.
3. The rail pressure control is in the limp-home function.
4. The rail pressure is limited to approximately 800 bar.