AIC 521465.09 – Missing Message from Engine Speed Control Module. John Deere System Advisory.

AIC 521465.09 (AIC )

Code: 521465.09



This error code indicates a failure in communication between the Armrest Interface Control Software (AIC) and the engine speed control module. The specific issue involves the AIC not receiving the expected LIN message from the engine speed control module, which is critical for coordinating engine operations.


In response to this communication gap, the control unit has limited the functionality of the engine control system to prevent possible misoperations and ensure safety under compromised data transmission conditions.


  • Check Communication Links: Inspect the LIN communication lines between the AIC and the engine speed control module for any signs of damage, disconnection, or interference that might be causing the message loss.
  • Diagnostic Testing of Modules: Perform diagnostic tests on the engine speed control module to verify its operational status and its ability to send and receive LIN messages accurately.
  • Restore and Secure Connections: Repair or replace any faulty components within the communication network. Ensure all connections are secure and properly shielded to prevent interference.
  • Software and Firmware Review: Update or reconfigure the software and firmware settings in both the AIC and the engine speed control module to correct any discrepancies or bugs that could be affecting communication.
  • System Reset and Test: After implementing repairs and adjustments, reset the control systems and perform rigorous testing to ensure that messages are being transmitted and received without any issues.


It’s critical to maintain the integrity of communication systems within agricultural machinery to ensure that all modules function harmoniously. Regular updates and checks on the software and hardware that facilitate these communications can prevent operational failures and optimize machinery performance.