PACCAR MX (2004 Emissions) Fault Code: P0108 Inlet Air Pressure in Inlet Manifold – Voltage Too High or Short Circuit to Supply on ECU (D420) Pin (A51)

SET CONDITIONS:
This DTC is set when the ECU detects a higher voltage than expected on the signal or control circuit of the ECU.

DIAGNOSTIC CONDITION:
This diagnosis runs continuously when the ignition is keyed ON.

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
This DTC cannot be cleared from the ECU memory.

REPAIR VERIFICATION:
1. Contact your engine field service representative for authorization to clear the warranty DTC.
2. Clear all DTCs.
3. Test drive or operate the vehicle to meet the following conditions:
– Diagnostic conditions are met
– Set conditions are met
4. Did the DTC come back? (Can be pending, inactive or active)
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
1. Boost pressure sensor wiring has a short circuit to supply.
2. Malfunction of the boost pressure sensor (F802)