JCB P2264 – Engine ECU: Water in Fuel Sensor Feedback Signal ADC Fault

The Engine Control Unit (ECU) has detected an issue with the feedback signal from the water-in-fuel sensor, specifically related to the Analog-to-Digital Conversion (ADC) process. The ECU is unable to properly interpret the analog voltage signal from the sensor, which affects the accuracy of the sensor's readings and the system's ability to monitor fuel quality. This can be caused by a fault in the sensor itself, the wiring, or the ECU's internal circuitry. The typical machine reaction is a torque reduction to protect the engine. Other potential symptoms include the illumination of the check engine light or water-in-fuel light, rough running, engine stalling or misfiring, and poor fuel economy.

• 1400B
• 1550B
• 1600B
• 1700B
• 214
• 215
• 216
• 217
• 3C
• 3CX
• 3D
• 3DX
• JS Series
• JS200
• JS220
• JS330
• Telehandlers

1. 1

   Retrieve fault codes using a diagnostic tool (like JCB ServiceMaster) to confirm P2264 is active and check for related codes (e.g., P2265, P2266, P2267, P2269). Document the freeze-frame data if available.

2. 2

   Inspect a fuel sample from the water separator bowl for visible water or contamination

3. 3

   Visually inspect the water-in-fuel sensor, its electrical connector, and the wiring harness for corrosion, damaged or frayed wires, loose connections, or rubbing against the chassis or engine components

1. 1

   Drain water separator

   If water was found during inspection, drain the fuel filter/water separator until all visible water is removed. Clear the fault codes, operate the machine, and check if the fault returns.

2. 2

   Check wiring and connectors

   Disconnect the water-in-fuel sensor connector and clean any corrosion. Perform a pull test on the wires. Check for continuity on the wiring harness between the sensor connector and the ECU (resistance should be close to 0 ohms). Check for a short to ground or power in the signal wire. Repair as needed.

3. 3

   Test the sensor

   With the key on, check for a 5V reference voltage being supplied to the sensor from the ECU. If the wiring is good but the fault persists, the sensor is likely providing an out-of-range voltage signal.

4. 4

   Replace sensor

   If the sensor is determined to be faulty, replace it. Clear the fault codes and run the machine to verify the repair.

5. 5

   Diagnose ECU

   If all other steps fail to resolve the issue, the fault may lie within the Engine Control Unit's internal analog-to-digital converter. This is the least common cause and should only be considered after exhausting all other possibilities.