PACCAR MX (2004 Emissions) Fault Code: P0088 Fuel Pressure – Data Valid but Too High

PACCAR MX (2004 Emissions) Fault Code: P0088 Fuel Pressure – Data Valid but Too High

SET CONDITIONS:
The PCI ECU (D420) detects that the fuel pressure is 14 bar [203 psi] or more for more than 10 seconds.

DIAGNOSTIC CONDITION:
This diagnostic runs when the engine has been running for more than 200 seconds.

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:
Shut-off valve in the fuel return pipe stuck in the closed position. Restriction in the fuel to tank return circuit or faulty fuel pressure control valve.

ADDITIONAL INFORMATION:
1. The low-pressure fuel pressure is measured by the fuel pressure sensor (F801).

2. Too high a pressure in the injector fuel return circuit can damage the electrical connectors of the injectors. Therefore, check the (white) connectors on the injectors for cracks if this DTC has been set.