Cummins ISX12 CM2250 (2010-12) Fault Code: 429 PID: SPN: 97 FMI: 4 Water-In-Fuel Indicator Sensor Circuit- Voltage Below Normal or Shorted to Low Source

Circuit Description
The water-in-fuel sensor is attached to the fuel filter. The electronic control module (ECM) provides a 5 volt reference signal to the water-in-fuel sensor. When the water collected in the fuel filter covers the sensor probes, the water-in-fuel sensor then pulls the 5 volt reference voltage to ground, indicating high water accumulation in the fuel filter.

Component Location
The water-in-fuel sensor is integrated into the bottom of the OEM-supplied suction fuel filter.

Conditions for Running the Diagnostics
This diagnostic runs continuously when the keyswitch is in the ON position.

Conditions for Setting the Fault Codes
The ECM detects that the water-in-fuel sensor signal voltage is below 0.05-VDC for 1 second.

Action Taken When the Fault Code is Active
The ECM illuminates the amber CHECK ENGINE light immediately when the diagnostic runs and fails.
Conditions for Clearing the Fault Code
To validate the repair, start the engine and let it idle for 1 minute.
The fault code status displayed by INSITE? electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
The ECM will turn off the amber CHECK ENGINE lamp after the diagnostic runs and passes.
The ?Reset All Faults? command in INSITE? electronic service tool can be used to clear active and inactive faults.

Shop Talk
Possible causes of this fault code include:

Signal circuit shorted to ground in the harness, sensor, or connector.
Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.

For intermittent power supply and datalink communication issues with Aftertreatment Components, it is highly recommended that the OEM Power Distribution Center fuses and relays be thoroughly checked for loose, missing or intermittent connections.

Possible Cause:
1) ECM failure
2) Engine Harness
3) ECM calibration