PACCAR MX (2004 Emissions) Fault Code: P0093 Common Rail Fuel Pressure – Sudden Pressure Drop

PACCAR MX (2004 Emissions) Fault Code: P0093 Common Rail Fuel Pressure – Sudden Pressure Drop

SET CONDITIONS:
The PCI ECU (D420) detects that the actual rail pressure drops suddenly.

DIAGNOSTIC CONDITION:
This diagnostic runs when the rail pressure operating state is: Pump unit 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. An external or internal fuel leakage on the high pressure fuel system components (e.g., fuel injection pipe)
2. A faulty fuel injector

ADDITIONAL INFORMATION:
1. The rail pressure is closed-loop controlled. A comparison is made between the requested and actual rail pressure 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.