AIC 521143.02 – CommandQuad™ Range Switch B Circuit Conflict. John Deere AIC System Alert.

AIC 521143.02 (AIC )

Code: 521143.02



This error code, AIC 521143.02, signals a malfunction within the CommandQuad™ transmission’s range switch B, where the ON and OFF contacts erroneously register the same value. This issue can cause confusion in the transmission system’s control logic, potentially leading to incorrect or unsafe gear selections.


As a precaution and to prevent potential transmission damage, the control unit has automatically engaged a recoverable PARK position, halting any further vehicle movement until the conflict is resolved.


  • Inspect range switch B for mechanical faults such as sticking or failure to return to a neutral position. Check for debris, wear, or damage that might cause the contacts to align incorrectly.
  • Utilize diagnostic tools to test the electrical functionality of the switch, ensuring that the ON and OFF states are being uniquely and accurately detected.
  • Check the wiring and connectors linked to range switch B for any signs of damage, corrosion, or loose connections that could affect signal transmission.
  • If necessary, replace the faulty switch or repair any identified issues within the circuit. Ensure all new installations or repairs adhere to the manufacturer’s specifications and are properly integrated into the system.
  • Recalibrate the switch settings after repairs are complete and perform a thorough system test to ensure that the transmission is functioning correctly without any further conflicts.


Consistent monitoring and maintenance of range switches are essential to prevent transmission issues in vehicles equipped with CommandQuad™ systems. Proactive management of these components ensures reliable operation, enhances safety, and reduces the risk of costly downtime.