PACCAR MX (2004 Emissions) Fault Code: P2266 Water in Fuel – Voltage Too Low or Short Circuit to Ground on ECU (D420) Pin (A49)

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

DIAGNOSTIC CONDITION:
This diagnostic runs continuously when the engine is running.

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
This DTC changes to inactive when the fault is no longer detected. To validate the repair, monitor the water in fuel sensor signal with the diagnostic service tool.

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. Open circuit or short circuit to earth in the wiring
2. Check the sensor voltage with the diagnostic service tool
3. Faulty water in fuel sensor

ADDITIONAL INFORMATION:
The water in fuel sensor is part of the fuel filtration module (L097).