CAB 524020.31 – Left-Hand Reverser Lever in Gear at Power Up

CAB 524020.31 (CAB )

Code: 524020.31



Error code CAB 524020.31 occurs when the CAB control unit detects that the left-hand reverser (LHR) lever is not in the neutral or park position at the time of vehicle power-up. This situation can lead to potential safety risks, as starting the vehicle with the lever engaged in a gear can cause unexpected movements.


To mitigate any risk of unintended vehicle movement, the control unit automatically commands the vehicle into a ‘Park’ state. This state is recoverable once the issue is addressed and the system is properly reset.


  • Check Lever Position at Startup: Ensure that the LHR lever is in the neutral or park position before starting the vehicle. Educate all operators on the importance of verifying the lever position to prevent this issue.
  • Inspect the Reverser Lever Mechanism: Conduct a thorough inspection of the reverser lever to check for any mechanical issues that could prevent it from returning to the neutral or park position.
  • Test Lever Sensors: Use diagnostic tools to test the sensors responsible for detecting the lever’s position. Ensure these sensors are accurately reporting the lever’s state to the control unit.
  • Adjust or Replace Faulty Components: If the lever or sensors are found to be faulty, make necessary adjustments or replace defective parts to ensure the lever correctly indicates its position.
  • Reset and Recalibrate the System: After ensuring the lever and its components are in proper working order, reset the control system to clear the fault and recalibrate if necessary to ensure accurate detection of the lever’s position.
  • System Functionality Verification: Perform tests to verify that the reverser lever operates correctly and that the vehicle does not start unless the lever is in the neutral or park position.


Regular preventative maintenance and operator training are key to ensuring that equipment starts safely and functions correctly. Ensuring that all operators understand the critical safety protocols, including the proper positions for controls at startup, is vital for preventing accidents and maintaining a safe working environment.

Control Units: John Deere

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