ECU 000028.00 – Primary Analog Throttle Signal Extremely High. John Deere Engine Control.

ECU 000028.00 (ECU 28.00)

Code: 000028.00

Shortcode: 28.00


The ECU 000028.00 (28.00) error code in John Deere equipment signals an issue where the primary analog throttle signal is recorded as extremely high, although paradoxically, the foot throttle sensor signal is much lower than expected. This discrepancy could be due to a faulty throttle sensor, incorrect wiring, or an issue within the engine control unit (ECU) that misreads the sensor’s output. Such a condition can lead to erratic engine behavior, such as unexpected acceleration or lack of response from the throttle pedal.


In response to this fault, the John Deere engine control system might limit throttle input to prevent uncontrollable engine speeds or erratic behavior, ensuring the safety of the operator and the integrity of the engine.


  • Inspect the Throttle Sensor and Wiring: Examine the throttle sensor and its wiring for signs of damage, disconnection, or corrosion that could affect signal transmission.
  • Test Sensor Output: Use diagnostic equipment to test the throttle sensor’s output to verify that it matches the expected parameters under various throttle positions.
  • Replace Faulty Sensor: If the throttle sensor or associated wiring is found to be defective, replace these components with genuine John Deere parts to restore proper function.
  • Reset the System and Test: After repairs, reset the engine control unit to clear the error code and conduct a test drive to ensure that the throttle operates correctly across all ranges of motion.


Regular checks and maintenance of the throttle system are crucial for preventing such discrepancies. Ensuring that all electrical connections are secure and free from corrosion helps maintain the reliability and performance of the throttle system. It’s also advisable to update the engine control software regularly to ensure it accurately interprets sensor signals and responds appropriately to throttle inputs.

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