Case IH 15263 - AST – Steering Valve Controller (SVC): AST: Cut-off solenoid stuck open. Spool movement test at transition from on-road to off-road failed.

When the operator attempts to switch the tractor from on-road mode to off-road mode, the steering controller performs an off-road safety check (a spool movement test) to verify the integrity of the steering valve. This code sets when the test fails because the cut-off solenoid valve is mechanically or hydraulically stuck in the open position. As a safety precaution, the controller will de-energize the cut-off solenoid, enter a safe state, and refuse to permit the transition to off-road mode, meaning electro-hydraulic steering will not be available.

• MAXXUM T4E
• VESTRUM CVX
• AFS Connect Magnum Tractors (Models 180, 200, 220, 240, 250, 280, 310, 340, 380)
• Vestrum CVX Series Tractors (Models 100, 110, 120, 130)

1. 1

   Verify that the steering valve is being supplied by sufficient hydraulic oil flow

2. 2

   Bleed the steering system by turning the steering wheel fully to the left, then fully to the right, a minimum of 10 times

3. 3

   Check for abnormal noise or vibration when steering after bleeding the system

4. 4

   Ensure the tractor is on a hard, on-road surface (unpainted concrete or asphalt) before performing any steering calibration or spool movement test

1. 1

   Hydraulic Bleed

   Start the machine and perform the manual steering bleed procedure (10 lock-to-lock turns) to rule out air cavitation causing the spool to hang up.

2. 2

   Clear and Retest

   Attempt to clear the fault code and transition from on-road to off-road mode on a concrete/asphalt surface to trigger the off-road safety check.

3. 3

   Inspect the Solenoid

   If the code returns immediately, locate the cut-off solenoid on the steering valve assembly. Check for physical damage, debris, or contamination in the hydraulic fluid that could cause the solenoid spool to stick open.

4. 4

   Replace Component

   If the solenoid is permanently stuck open and cannot be freed or cleaned, replace the cut-off solenoid valve. If the solenoid is integrated and cannot be serviced separately, the entire steering valve assembly must be replaced.

5. 5

   Recalibrate

   After replacing the solenoid or valve, re-bleed the hydraulic system (10 lock-to-lock turns) and perform the AST steering calibration using an electronic diagnostic tool to clear the safe state and restore electro-hydraulic steering.