PACCAR MX (2004 Emissions) Fault Code: P229D Common Rail Pressure Release Valve Current – Data Valid but Too High

PACCAR MX (2004 Emissions) Fault Code: P229D Common Rail Pressure Release Valve Current – Data Valid but Too High

SET CONDITIONS:
The PCI ECU (D420) detects that the common rail pressure release valve control current has been higher than expected for more than six seconds.

DIAGNOSTIC CONDITION:
This diagnostic runs when the rail pressure operating state is: Release valve only.

CORRESPONDING OBD READINESS MONITOR:
None

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 diagnostic conditions and set conditions.
3. Did the DTC come back?
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
1. Faulty common rail pump unit (too little fuel is pumped to the rail).
2. Leaking common rail pressure release valve.

ADDITIONAL INFORMATION:
1. The PCI ECU controls and checks the current of the common rail pressure release valve (L094). The current is controlled with a duty cycle.

2. When this DTC is active:
– the engine torque is reduced.
– the engine runs in protection mode.
– the rail pressure control is: Pump unit only.
– the rail pressure is limited to approximately 1300 bar.