PACCAR MX (2004 Emissions) Fault Code: P1089 Common Rail Fuel Pressure – Data Valid but Too High

PACCAR MX (2004 Emissions) Fault Code: P1089 Common Rail Fuel Pressure – Data Valid but Too High

SET CONDITIONS:
The PCI ECU (D420) detects that the measured rail pressure is more than 2840 bar [41191 psi].

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

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 common rail pump unit

ADDITIONAL INFORMATION:
1. The rail pressure is measured in the common rail by the common rail pressure sensor (F854).

2. When this DTC is active:
– The engine torque is reduced.
– The engine runs in protection mode.
– The engine runs in rail pressure control state: Release valve only.
– The maximum rail pressure is limited to 1300 bar.