John Deere SSU522273.01 – SSU: Steering Valve Control Circuit Problem

The Steering System Control Unit (SSU) has detected that the electrical signal to the electro-hydraulic steering valve is below the expected range. This indicates a potential issue with the wiring, connections, or the steering valve itself, which compromises the AutoTrac assisted steering system.

• 9230
• 9330
• 9430
• 9530
• 9630
• 7720
• 7820
• 7920
• 7630
• 7730
• 7830
• 7930
• 8R Series
• 8RT Series
• 4930

1. 1

   Restart the vehicle to cycle the power, which can sometimes clear communication-related faults

2. 2

   Inspect fuse F23, which is associated with SSU voltage problems

3. 3

   Ensure the hydraulic oil is at operating temperature, as low temperatures can affect system performance

4. 4

   Visually examine the wiring harness and connectors between the SSU and the electro-hydraulic steering valve for damage, corrosion, or loose connections. Note that a wiring harness issue between the hydraulics and the steering sensor has been noted as a potential cause

5. 5

   Check for other active SSU fault codes that may provide additional context to the primary issue

6. 6

   Check the load sense signal to isolate potential leaks in the hydraulic circuit

7. 7

   Inspect specific SSU addresses using dealer-level diagnostic tools

1. 1

   Perform preliminary diagnostics

   Complete all the diagnostic checks listed in the preliminary checks section.

2. 2

   Test steering valve circuit

   If the preliminary checks do not resolve the issue, check for proper voltage, continuity, and any shorts to ground in the wiring between the SSU and the steering valve. This requires a model-specific wiring diagram and pinout chart.

3. 3

   Calibrate steering system

   Perform an AutoTrac valve calibration through the machine's display. Turn the steering wheel to its stops and allow the system to automatically calibrate the valve deadband. Repeated calibration failures indicate a hardware problem.

4. 4

   Replace electro-hydraulic steering valve

   If wiring is intact and calibration fails, lower the bracket holding the valve, clean the area thoroughly, remove the four Allen head cap screws, and remove the old valve and O-rings. Install the new valve (or PVE electronic portion) with new O-rings and re-secure.

5. 5

   Post-repair verification

   Clear all fault codes and test the AutoTrac system to ensure the steering issue is fully resolved.