AIC 523954.11 – Mismatched Output Signals in Speed Control Lever Sensor Unit. John Deere System Advisory.

AIC 523954.11 (AIC )

Code: 523954.11



This error code AIC 523954.11 indicates a problem with the sensor unit of the speed control lever, specifically the speed wheel. There is a discrepancy between the output signals from channels 1 and 2, suggesting an incorrect combination of signals that could affect the operation of the speed control system. This issue might occur due to a fault within the sensor unit or potentially from the operator constantly adjusting the speed up or down by one count, which could lead to signal misinterpretation by the control system.


Due to the mismatch in sensor output signals, the control unit has restricted the ability to adjust set speeds on the vehicle, thereby preventing potential errors in speed setting adjustments until the issue is resolved.


  • Inspect the Sensor Unit and Associated Wiring: Check the speed control lever’s sensor unit, focusing on the speed wheel and related wiring. Look for signs of damage, wear, or improper connections that could contribute to signal discrepancies.
  • Test Output Channels: Utilize diagnostic tools to test the output signals from channels 1 and 2. Verify that the signals are being generated correctly and observe any irregularities or fluctuations.
  • Calibrate or Reset the Sensor Unit: If the signals are found to be mismatched, recalibrate the sensor unit to correct the outputs. If calibration does not resolve the issue, consider resetting the sensor unit to its factory settings.
  • Review Operator Usage: If the problem may be due to operator handling, provide guidance on the correct usage of the speed control lever to avoid constant minor adjustments that could affect signal outputs.
  • Replace Faulty Sensor if Necessary: Should recalibration and resetting fail to correct the signal mismatch, replace the sensor unit to ensure accurate and reliable performance.
  • System Reset and Comprehensive Testing: After making the necessary adjustments or replacements, reset the control system to clear any error states. Perform a comprehensive functional test to ensure that the speed control lever and its sensor unit are operating correctly and that set speeds can be adjusted accurately without issues.


Regular monitoring and maintenance of sensor units and their output signals are essential for maintaining the accurate operation of vehicle control systems. Immediate attention to and resolution of signal discrepancies can prevent operational inefficiencies and ensure that the machinery operates safely and effectively under all conditions.