AIC 521421.02 – Communication Error in Armrest Hitch Controls Module. John Deere System Notification.

AIC 521421.02 (AIC )

Code: 521421.02



This error code reports a communication error in the Armrest Hitch Controls Module, characterized by an incorrect LIN Bus message from the LIN Bus Module at Position M. The issue indicates a data transfer problem between the AIC control software and the LIN Bus module responsible for hitch control, suggesting a fault within the LIN Bus system or the transmitting module itself.


The control unit has moved to a limited function mode in response to this communication fault, restricting certain functionalities to prevent erroneous operations and potential damage.


  • Inspect the LIN Bus System: Examine the LIN Bus and its components, particularly at Position M, for signs of physical damage or disconnection that could be interfering with data transmission.
  • Diagnose the LIN Bus Module: Use diagnostic tools to test the functionality and integrity of the LIN Bus module, focusing on its ability to transmit and receive messages correctly.
  • Rectify Wiring and Connectivity Issues: Check for and repair any faulty wiring or poor connections that might be affecting the communication lines within the LIN Bus system.
  • Replace Faulty Modules if Necessary: If diagnostics indicate a malfunction in the LIN Bus module, consider replacing it to ensure reliable data transfer and system operation.
  • System Reset and Testing: After addressing the identified issues, reset the system to clear any error states and conduct thorough tests to ensure that all components are functioning correctly and the hitch controls are fully operational.


Maintaining a robust and error-free communication network within agricultural machinery is crucial for operational efficiency and safety. Regular checks and maintenance of the LIN Bus system and its modules can help prevent communication errors and minimize downtime, thereby enhancing the machinery’s overall performance and reliability.