ACU 002000.09 (ACU 2000.09 ) – Communication Breakdown with ECU

ACU 002000.09 (ACU 2000.09)

Code: 002000.09

Shortcode: 2000.09


The error code ACU 2000.09 is triggered when the armrest control unit fails to receive the necessary messages from the Engine Control Unit (ECU). This failure in communication can significantly impact the coordination and management of engine functions.


Due to the lack of critical data from the ECU, the control unit defaults the machinery to idle mode, disables throttle functions, and commands the vehicle into PARK to ensure safety.


  • Check the integrity and security of all communication links between the armrest control unit and the ECU. Ensure all connections are secure and free of corrosion or damage.
  • Use diagnostic tools to verify the continuity and quality of the signal being transmitted to and from the ECU.
  • Inspect the ECU for faults or errors that might be preventing it from sending the required messages. This may include looking for error codes specifically related to the ECU itself.
  • Consider resetting both the ECU and the armrest control unit to re-establish default settings and connections.
  • If communication issues persist, it might be necessary to replace faulty wiring or even parts of the control unit or ECU as directed by a John Deere service technician.


This issue is critical as it directly affects the operational capabilities of the equipment. Timely resolution is essential to prevent operational downtime and ensure safety compliance.