ECU 000091.04 – Primary Analog Throttle Signal Out of Range Low. John Deere Engine Control.

ECU 000091.04 (ECU 91.04)

Code: 000091.04

Shortcode: 91.04


The ECU 000091.04 (91.04) error code indicates that the primary analog throttle signal on John Deere machinery is below the low voltage specification for the foot throttle sensor. This under-voltage could result from a faulty sensor, poor wiring, or a disconnection, potentially leading to inadequate throttle response or engine underperformance.


To prevent inadequate operation, the engine control system may reduce the throttle’s responsiveness or initiate a limp mode, safeguarding both the engine’s functionality and the operator’s safety.


  • Examine Throttle Sensor and Electrical Connections: Inspect the sensor and its connections for any signs of wear, corrosion, or disconnections.
  • Measure Sensor Voltage: Conduct tests with diagnostic equipment to measure the voltage outputs from the throttle sensor.
  • Repair or Replace Components: Replace any damaged or malfunctioning parts with original John Deere components to restore normal operation.
  • System Reset and Verification: Reset the engine control unit to clear the error code, then test thoroughly to ensure correct throttle operation.


Regular maintenance, especially in harsh operating environments, is vital to prevent voltage issues in the throttle system. Ensuring that all sensors are correctly calibrated and functioning within their specified ranges is essential for optimal performance.

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