Case IH 15322 - AST – AST (Advanced Steering / Auto Steer) control subsystem: Steering valve controller failure - LVDT signal B out of range

The LVDT sensor inside the electrohydraulic steering valve actuator measures the physical position of the steering spool. This fault indicates that the voltage or feedback from Signal B has fallen outside of its calibrated or expected operating range, preventing the controller from reliably verifying the spool position and forcing the auto-guidance system into a safe/disabled state.

• MAXXUM T4E
• VESTRUM CVX
• Magnum series
• Steiger series
• Optum series
• Puma series

1. 1

   Inspect the wiring harness and main connector at the PVED-CLS steering valve for moisture, corrosion, or backed-out pins

2. 2

   Verify the power supply to the PVED-CLS controller (voltage drops below 9V can cause erratic behavior and trigger faults)

3. 3

   Verify that the LVDT offset compensation is enabled using the OEM diagnostic tool (parameter P3089 should be set to 255)

4. 4

   Attempt to run a spool calibration via the diagnostic tool to see if the LVDT can successfully re-learn its neutral and end-of-stroke positions

1. 1

   Relieve hydraulic pressure

   Park the tractor on a level surface, turn off the engine, and relieve all hydraulic pressure from the steering circuit.

2. 2

   Disconnect harness

   Disconnect the electrical harness from the PVED-CLS steering valve controller.

3. 3

   Remove actuator

   Unbolt and remove the faulty PVED-CLS actuator from the main steering valve block.

4. 4

   Install new controller

   Install the new PVED-CLS controller onto the valve block, ensuring all O-rings/seals are properly seated.

5. 5

   Reconnect harness

   Reconnect the electrical harness.

6. 6

   Perform calibration

   Connect the Case IH Electronic Service Tool (EST) and perform a mandatory spool calibration to cancel out mechanical and electrical tolerances and learn the mechanical dead-bands.

7. 7

   Clear fault and test

   Clear the 15322 fault code and test the auto-guidance steering in an open area.