AIC 521405.02 – SCV XII Control Lever Switch/Sensor Conflict. John Deere AIC System Alert.

AIC 521405.02 (AIC )

Code: 521405.02



This error code highlights a malfunction in the SCV XII (Selective Control Valve XII) system where the detent switch conflicts with the actual lever position. Additionally, the signal voltage from the SCV XII control lever is reported to be out of the designated range or misaligned with the statuses of the switch and potentiometer, leading to operational discrepancies.


Due to the detected discrepancies and in order to prevent potential operational errors or safety issues, the system has automatically restricted the functionality of the SCV XII control lever.


  • Inspect the SCV XII control lever and its associated detent switch for mechanical wear, damage, or any obstructions that might affect the switch’s accurate detection of the lever position.
  • Use diagnostic equipment to measure and verify the signal voltage levels of the SCV XII control lever to ensure they are within the normal operational range and correspond accurately to lever movements.
  • Check the electrical wiring and connections related to the SCV XII lever for signs of damage or disconnections that could contribute to the voltage conflicts.
  • Address any identified issues by repairing or replacing faulty components, ensuring all parts are correctly installed and integrated into the system.
  • After making necessary repairs or adjustments, recalibrate the control settings for the SCV XII lever and conduct thorough operational tests to confirm that the system functions correctly without any further sensor conflicts.


Regular maintenance of control levers and their sensors is essential for the smooth operation of hydraulic systems in agricultural machinery. Ensuring that all components are functioning correctly and that sensors accurately reflect the lever positions is crucial for maintaining the effectiveness and safety of the equipment’s operations. Proactive management and timely intervention are key to avoiding downtime and ensuring reliability.