ECU 000097.04 – Water-in-Fuel Filter Signal Voltage Low. John Deere Engine Control.

ECU 000097.04 (ECU 97.04)

Code: 000097.04

Shortcode: 97.04


The ECU 000097.04 (97.04) error code on John Deere equipment indicates that the voltage from the water-in-fuel sensor is below the lower limit specified for low sensor voltage. This condition typically suggests a short to ground within the sensor’s circuitry. Causes can include damaged insulation, corroded connectors, or a grounding issue in the wiring. A low voltage signal can prevent the sensor from accurately detecting water presence in the fuel, potentially risking engine health if water is not effectively signaled.


Upon detecting this low voltage condition, the engine control system might disregard the sensor input, potentially failing to alert operators of water in the fuel system, which could lead to engine damage or efficiency problems.


  • Inspect Sensor and Wiring: Check the water-in-fuel sensor and its wiring thoroughly for any signs of wear, damage, or corrosion that might contribute to a grounding problem.
  • Test Electrical Circuit: Use diagnostic tools to evaluate the electrical circuit for faults or inconsistencies that could explain the low voltage issue.
  • Replace Damaged Parts: Should any components of the sensor or wiring be found defective, replace them with original John Deere parts to restore proper sensor function.
  • System Reset and Testing: After repairs, reset the engine control system to clear the fault codes and test the system to ensure the sensor now correctly detects water in the fuel.


Maintaining the integrity of the water-in-fuel sensor and its connections is crucial for engine protection. Regular checks should be part of routine maintenance to ensure that the sensor and its circuitry are free from damage and corrosion. It’s also essential to ensure that all fuel system sensors are properly grounded and isolated from potential sources of electrical interference to maintain accuracy and reliability in their readings.

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