AIC 523670.02 – Speed Control Lever Signal Mismatch. John Deere System Notification.

AIC 523670.02 (AIC )

Code: 523670.02



The error code AIC 523670.02 identifies a signal mismatch within the speed control system of the tractor. Specifically, there is a conflict between the signal from the switch for speed band 2 and the signal from the potentiometer of the speed control lever. Although the switch for speed range 2 is activated, the lever position corresponds to speed range 1. This discrepancy indicates a potential issue with either the switch, the potentiometer, or the wiring connecting these components.


Due to this mismatch, the control software has disabled tractor movement to prevent operational errors or potential damage. The tractor defaults to neutral and cannot be moved until the diagnostic trouble code is addressed. Once the fault is corrected, the tractor can be driven by moving the reverse drive lever through the corner park position.


  • Inspect the Speed Control Lever and Associated Switches: Examine the speed control lever and the switch for speed band 2 for any signs of physical damage, misalignment, or wear that could affect their operation.
  • Test the Potentiometer and Switch Signals: Use diagnostic tools to measure the output signals from both the potentiometer and the switch. This will help determine whether the signals are within their specified ranges and behaving as expected.
  • Diagnose Electrical Connections: Check the wiring and connections between the speed control lever, the switch, and the control unit for any loose, damaged, or corroded connections that might be causing signal issues.
  • Repair or Replace Faulty Components: Depending on the findings, repair or replace any faulty switches, potentiometers, or wiring to resolve the signal mismatch.
  • Calibrate the Speed Control System: After repairs or replacements, calibrate the speed control system to ensure all components are correctly synchronized and functioning as intended.
  • System Reset and Functional Testing: Reset the control system to clear any fault states. Perform a full operational test to confirm that the tractor operates correctly in all speed ranges and that the issue has been fully resolved.


Regular maintenance and prompt attention to issues within the control systems of agricultural machinery are crucial for ensuring reliable operation and preventing downtime. Addressing electrical and signal discrepancies quickly helps maintain the efficiency and safety of the equipment.