ACU 523960.31 – Unattended Reverser Activation

ACU 523960.31 (ACU )

Code: 523960.31



Error code ACU 523960.31 occurs when a direction change is commanded via the reverser while the operator’s presence is not detected in the seat. This situation poses significant safety risks due to potential uncontrolled vehicle movements.


To prevent any unsafe operation, the control unit responds by automatically shifting the machinery into PARK mode, thereby halting any movement until the operator is properly seated.


  • Inspect the operator seat sensor to ensure it is functioning correctly. Look for any signs of wear, damage, or misalignment that might affect its ability to detect the operator’s presence.
  • Test the reverser controls to verify that they are operating correctly and only responding when the operator is detected in the seat.
  • Review the machinery’s safety protocols and settings in the control system to ensure that they are configured to respond appropriately to such scenarios.
  • Recalibrate or replace the operator presence sensor if tests indicate it is not functioning properly. Follow the manufacturer’s guidelines to ensure correct installation and operation.
  • Train all operators to understand the importance of being properly seated with all safety equipment engaged before and during the operation of machinery, especially when initiating direction changes.


Maintaining rigorous safety standards and ensuring that all safety sensors and protocols are operational is crucial for preventing accidents. Regular checks and training can help reinforce safe practices and ensure the equipment operates safely and efficiently.