ECU 000084.31 – Incorrect CAN BUS Message, Wheel Speed from BCU. John Deere Engine Control.

ECU 000084.31 (ECU 84.31)

Code: 000084.31

Shortcode: 84.31


The ECU 000084.31 (84.31) error code identifies a communication problem on John Deere equipment involving the CAN BUS message regarding wheel speed, transmitted from the Brake Control Unit (BCU) to the Engine Control Unit (ECU). The issue arises due to intermittent or nonexistent reception of one or more CAN messages, potentially caused by a loose wire, incorrect wheel speed sensor configuration, improper installation, or a defective sensor or lead (specifically lead 5001). This fault is detected when the BCU reports a wheel speed to the ECU that is slower than what the ECU itself has registered.


When this error occurs, the ECU may initiate a fail-safe mode to mitigate any potential risk caused by incorrect wheel speed readings, which can affect braking efficiency and vehicle stability.


  • Inspect Wheel Speed Sensor and Wiring: Thoroughly check the wheel speed sensor and associated wiring, particularly lead 5001, for any signs of damage, disconnection, or wear that could affect data transmission.
  • Verify Sensor Installation and Configuration: Ensure that the wheel speed sensor is correctly installed and configured according to John Deere’s specifications. Misconfiguration can lead to erroneous signals being sent to the ECU.
  • Check CAN BUS Connections: Examine the CAN BUS connections for any loose connections or corrosion that might interfere with communication between the BCU and ECU.
  • Replace Faulty Components: If a defective sensor or wiring is identified, replace it with genuine John Deere parts to restore proper functionality.
  • Reset and Recalibrate the System: After repairs, reset the error codes and recalibrate the sensor to ensure accurate data is communicated to the ECU. Perform a test drive to verify that all systems are functioning as expected.


This error highlights the importance of maintaining the integrity of sensor signals and communication pathways within the vehicle’s network. Regular checks and maintenance of the CAN BUS system and wheel speed sensors can prevent such faults. It is also advisable to ensure that all firmware and software updates provided by John Deere are applied to keep vehicle systems up to date and functioning correctly.

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