New Holland ENG 3423 – ENGINE ECU: Fuel Filter Sensor: Implausible Value

This code indicates that the Engine Control Unit is receiving an erratic, illogical, or out-of-range signal from the fuel filter sensor (commonly known as the Water-in-Fuel or WIF sensor). Because related codes (like 3421 and 3422) specifically flag voltage that is strictly too high or too low, an "implausible value" usually points to a sensor that is failing internally, a severely contaminated fuel filter (heavy water/sludge presence), or an intermittent wiring issue.

• L213
• L216
• L218
• L220
• L221
• L223
• L225
• L230
• L318
• L320
• C227
• C232
• C238
• B90B
• B95B
• B95C
• B100B
• B110B
• B115B
• W50C
• W60C
• W70C
• W80C
• T4.100
• T4.110F
• T5.95
• T5.120
• Boomer 40
• Boomer 50
• LM7.42

1. 1

   Drain the Water Separator: Place a pan under the fuel filter and open the drain valve. If a large amount of water or sludge drains out, the sensor was likely reading an implausible value due to heavy contamination. Clear the code and see if it returns.

2. 2

   Visual Wiring Inspection: Inspect the wiring harness and the electrical pigtail connector at the bottom of the fuel filter. Look for corrosion, broken wires, or loose connections that could cause an intermittent signal.

3. 3

   Circuit Testing: Use a multimeter to check the sensor wiring for a short circuit to the battery or ground.

4. 4

   Filter Condition: Verify if the fuel filter is clogged or overdue for a routine change, as severe restriction can sometimes trigger related fuel system codes.

1. 1

   Turn off the machine and locate the engine fuel filter assembly.

2. 2

   Carefully disconnect the electrical wire connector from the fuel filter sensor located at the bottom of the filter element.

3. 3

   Place a drain pan underneath and loosen the sensor/drain plug to empty the fuel and water from the filter.

4. 4

   Remove the fuel filter element from the main filter body.

5. 5

   Unscrew and remove the fuel filter sensor from the bottom of the old filter element.

6. 6

   If replacing the sensor, discard the old one. If you are only replacing the filter, clean and inspect the existing sensor.

7. 7

   Thread the new (or cleaned) fuel filter sensor into the bottom of the new fuel filter element.

8. 8

   Attach the new filter element to the filter body.

9. 9

   Reconnect the electrical wire connector to the fuel filter sensor.

10. 10

    Ensure the drain plug is tight, then bleed the air from the fuel system according to your specific model's operator manual before attempting to start the engine.