BRC 000639.12 – CAN Message Overflow in Brake Control Unit. John Deere System Advisory.

BRC 000639.12 (BRC 639.12)

Code: 000639.12

Shortcode: 639.12


Error code BRC 000639.12 refers to an overflow of CAN (Controller Area Network) messages within the Brake Control Unit (BRC), primarily caused by the malfunction of an intelligent device or component. This condition indicates that the BRC has not received the expected messages from other components, likely due to excessive or corrupt data transmission.


The response to this issue is to disable the function of the Brake Control Unit, effectively turning it OFF. This preventive measure is taken to avoid erroneous operations based on potentially incorrect or missing data from other systems.


  • Identify and Replace Faulty Components: Diagnose the CAN network to identify which device or component is sending excessive messages or failing to communicate correctly. Replace or repair the faulty unit to restore proper communication.
  • Clear CAN Message Buffer: Check and clear the CAN message buffer in the BRC to prevent overflow and ensure it can receive new, correct messages.
  • Update Software/Firmware: Ensure that all components on the CAN network, including the BRC, are operating with the latest software or firmware versions that might include improvements or fixes for handling CAN message traffic.
  • System Reset and Testing: After addressing the issues, reset the Brake Control Unit and the associated network components. Perform a thorough test to ensure the system now operates correctly and can handle CAN messages without overflow.
  • Monitor Network Traffic: Regularly monitor CAN network traffic to detect early signs of message overflow or communication bottlenecks, which could prevent similar issues in the future.


The integrity and smooth operation of the CAN network are crucial for the coordinated functioning of various vehicle components, including safety-critical systems like brakes. Regular monitoring and maintenance are essential to ensure that all parts communicate efficiently and without disruption, maintaining the overall safety and functionality of the equipment.