ACU 000629.11 (ACU 629.11 ) – Critical RAM Memory Check Failure

ACU 000629.11 (ACU 629.11)

Code: 000629.11

Shortcode: 629.11


Error code ACU 629.11 identifies a failure in the Random Access Memory (RAM) check during the control unit’s start-up process. This indicates that the RAM, which is essential for the control unit’s operations, is potentially corrupted or malfunctioning.


Despite this critical memory failure, the control unit does not initiate a default response, which may leave the system operational but with potential instability or unpredictable behavior.


  • Restart the control unit to see if the RAM check error persists; sometimes, transient errors can be cleared with a simple reboot.
  • Conduct a diagnostic test specifically focusing on the RAM to determine if there are permanent faults. This might require specialized diagnostic tools that can be provided by John Deere service centers.
  • If RAM issues are confirmed, consider replacing the faulty memory module. This task should ideally be handled by qualified technicians to ensure proper handling and installation.
  • Regularly update all firmware and software as recommended by John Deere to prevent compatibility issues or bugs that might impact memory operations.


No immediate default response from the control unit can lead to undetected operational risks. It’s crucial to address this error promptly to ensure that the control unit remains reliable and effective in its functions.