PACCAR MX (2004 Emissions) Fault Code: P228C Common Rail Fuel Pressure Control – Incorrect

PACCAR MX (2004 Emissions) Fault Code: P228C Common Rail Fuel Pressure Control – Incorrect

SET CONDITIONS:
The PCI ECU (D420) detects that the measured rail pressure is more than 200 bar higher than the commanded rail pressure for more than 9 seconds.

DIAGNOSTIC CONDITION:
This diagnostic runs when the rail pressure operating state is: Pump unit only.

CORRESPONDING OBD READINESS MONITOR:
Fuel system monitor

RESET CONDITION:
This DTC changes to inactive when the fault is no longer detected.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the following conditions:
– Corresponding readiness monitor displays ‘Ready’
– Diagnostic conditions are met
– Set conditions are met
3. Did the DTC come back?
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
Common rail pump unit failure

ADDITIONAL INFORMATION:
1. The rail pressure is closed-loop controlled. A comparison is made between the rail pressure commanded by the ECU and the rail pressure feedback measured by the common rail pressure sensor.

2. The rail pressure is measured in the common rail by the common rail pressure sensor (F854).

3. When this DTC is active:
– The engine torque is reduced.
– The engine runs in protection mode.
– The maximum rail pressure is limited to 1300 bar.