AIC 521399.02 – SCV VIII Control Lever Switch/Sensor Conflict. John Deere AIC System Alert.

AIC 521399.02 (AIC )

Code: 521399.02



This error code highlights a conflict between the detent switch and the actual position of the SCV VIII (Selective Control Valve VIII) control lever. The inconsistency occurs when the detent switch, which is designed to detect the lever’s position, sends signals that do not correspond with the lever’s physical location. This misalignment can disrupt the proper operation of the hydraulic systems controlled by SCV VIII.


In response to the detected conflict, the system has restricted the functionality of the SCV VIII to prevent incorrect hydraulic actions that could lead to operational inefficiencies or safety concerns.


  • Physically inspect the SCV VIII control lever and its detent switch for signs of mechanical wear, improper installation, or any obstructions that might affect the switch’s accurate detection of the lever’s position.
  • Utilize diagnostic equipment to test the functionality of the detent switch to ensure it accurately reflects the position of the lever across its entire range of motion.
  • Examine the electrical connections and wiring of the SCV VIII control lever system for potential damage or wear that might be causing incorrect signal transmission.
  • If misalignment or malfunction is found, adjust, repair, or replace the detent switch to ensure it aligns correctly with the mechanical positions of the lever. Calibration of the switch may be necessary after making adjustments or replacements.
  • Conduct comprehensive operational tests to verify that the SCV VIII control lever and its associated detent switch are functioning correctly without conflicts, ensuring all hydraulic operations are performing accurately and safely.


Ensuring the precise alignment and functionality of control levers and their sensors is crucial for the efficient and safe operation of hydraulic systems in heavy machinery. Regular checks and maintenance of these components are vital to prevent operational issues and maintain optimal performance.