PACCAR MX (2004 Emissions) Fault Code: P1234 Common Rail Pump Unit 2 – Short Circuit Between ECU (D420) Pin (A27) and Pin (A28)
PACCAR MX (2004 Emissions) Fault Code: P1234 Common Rail Pump Unit 2 – Short Circuit Between ECU (D420) Pin (A27) and Pin (A28)
SET CONDITIONS:
The PCI ECU (D420) detects a short circuit between ECU pin A27 and pin A28.
DIAGNOSTIC CONDITION:
This diagnostic runs continuously when the ignition is on.
CORRESPONDING OBD READINESS MONITOR:
None
RESET CONDITION:
This DTC changes to inactive after the ignition has been switched off for at least 15 seconds and switched on again and 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:
Malfunctioning of the common rail pump unit 2 (L093) or wiring
ADDITIONAL INFORMATION:
When this DTC is active:
1. The engine torque is reduced.
2. The engine runs in protection mode.
3. The maximum rail pressure is limited to 1300 bar.
