ACU 523955.31 – Engine Overload in Manual Mode

ACU 523955.31 (ACU )

Code: 523955.31



The error code ACU 523955.31 is triggered when the engine experiences an overload while operating in manual mode. This condition typically occurs when the engine load exceeds safe operational limits, potentially due to improper handling or settings adjustments.


To prevent damage from excessive load, the control unit has limited certain functions, reducing the operational capacity of the engine to safer levels.


  • Ensure that the AutoPowr/IVT transmission selector switch is not in the OFF position while operating the engine, as this can lead to higher than intended loads.
  • If the OFF position is selected, operate the engine at wide open throttle and use the drive lever or set speed adjuster to control ground speed, as per the manufacturer’s advice.
  • Monitor engine load closely, especially when operating in manual mode, to ensure that it remains within the manufacturer’s recommended limits.
  • Review and adjust the operational settings and parameters to prevent overloading, particularly in conditions that demand high power or torque.
  • Conduct regular maintenance checks on the engine and transmission system to ensure that all components are in good working order and capable of handling the expected loads.


Continuous monitoring and adjustment of engine settings are crucial, especially when operating in manual mode, to avoid overloading and subsequent limited functionality. Training for operators on the appropriate settings and handling procedures can significantly reduce the occurrence of such issues.