SSU 000629.12 – Control Unit Internal Fault

SSU 000629.12 (SSU 629.12)

Code: 000629.12

Shortcode: 629.12


This diagnostic trouble code (DTC), SSU 000629.12, is triggered if the SSU control unit detects that too much time has elapsed (watchdog timeout). This indicates an internal timing issue within the SSU.


When this error is detected, the control unit may stop functioning correctly, potentially affecting the performance of the steering system.


Perform a System Reset:

  • Try resetting the SSU to clear temporary faults. Follow the manufacturer’s procedure for performing a system reset.

Check Power Supply:

  • Verify that the SSU is receiving a stable power supply within the specified voltage range.
  • Inspect the power connections for any signs of damage or loose connections.

Update Software:

  • Ensure that the SSU software is up-to-date. Apply any available firmware updates to address potential software-related issues.

Replace Faulty Components:

  • If the internal timing issue persists, replace the SSU control unit with a new, genuine part.

Consult Technical Support:

  • If the error persists after performing the above steps, consult technical support or the manufacturer for further assistance in identifying and resolving the issue.


  • Regular maintenance and inspection of the control unit and its connections can help prevent internal faults.
  • Keeping the SSU firmware up-to-date ensures compatibility and reliability of the vehicle’s systems.

Control Units: John Deere

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