AIC 521136.02 – CommandQuad™ Range Switch A Circuit Conflict. John Deere AIC System Alert.

AIC 521136.02 (AIC )

Code: 521136.02



This error code, AIC 521136.02, highlights a malfunction within the CommandQuad™ transmission system’s range switch A, where both the ON and OFF contacts are simultaneously registering the same value. This abnormal condition can confuse the transmission control system, causing erroneous responses or preventing proper gear selection.


Due to this conflict, the control unit has restricted the functionality of the transmission to a limited set of operations to avoid incorrect gear engagement and ensure safety.


  • Inspect range switch A for any mechanical issues such as sticking, wear, or damage that might cause it to fail to return to its neutral position or incorrectly register its state.
  • Test the switch using diagnostic tools to verify electrical functionality and ensure that the ON and OFF states are being uniquely and accurately detected.
  • Check the wiring and connectors linked to range switch A for any signs of damage, corrosion, or loose connections that could affect signal transmission.
  • If necessary, replace the faulty switch or repair any issues found in 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.