PACCAR MX (2004 Emissions) Fault Code: P1087 Fuel Pressure – Data Valid but Too Low, Moderately Severe

SET CONDITIONS:
The PCI ECU (D420) detects that the fuel pressure is too low for more than 50 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:
Faulty fuel pressure control valve Restriction in the fuel supply or low performance of the fuel lift pump.

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