Case IH 15264 - AST – Steering Valve Controller: AST: Cut-off solenoid stuck closed. Spool movement test at transition from on-road to off-road failed.

The AST system runs an automated diagnostic spool movement test whenever the tractor transitions from on-road (transport) mode to off-road (field) mode. During this transition, the system commands the cut-off solenoid to actuate. Code 15264 is triggered when the system detects that the cut-off solenoid has failed to open and is physically or electrically stuck in the closed position, preventing proper hydraulic flow for the auto-guidance/steering system.

• MAXXUM T4E
• VESTRUM CVX
• Optum
• Steiger

1. 1

   Verify the roading switch is functioning correctly and not stuck, as the spool movement test is triggered by the transition from on-road to off-road mode.

2. 2

   Check the wiring harness and connectors leading to the AST steering valve controller and the cut-off solenoid for corrosion, loose pins, or damaged wires.

3. 3

   Test the electrical resistance of the cut-off solenoid coil to ensure it has not shorted out or failed internally.

4. 4

   Inspect the hydraulic fluid for debris or contamination, which is a primary cause of a spool or solenoid physically sticking closed.

1. 1

   Safely park the tractor on a level surface, engage the parking brake, and turn off the engine.

2. 2

   Locate the AST steering valve block on the machine.

3. 3

   Disconnect the electrical harness from the cut-off solenoid and clean the connector pins.

4. 4

   If the electrical circuit is receiving the proper voltage command but the valve is not actuating, remove the cut-off solenoid from the steering valve assembly.

5. 5

   Inspect the valve spool and the solenoid cavity for debris, metal shavings, or scoring that would cause it to bind and stick closed.

6. 6

   If the solenoid is faulty or mechanically stuck, replace the cut-off solenoid.

   Note: If the internal spool of the main steering valve is severely scored, the entire steering valve assembly will require replacement.

7. 7

   Reinstall the components and reconnect the wiring harness.

8. 8

   Enter the diagnostic mode via the instrument cluster (navigate to the R1 module, menu H3, and select the AST system) or use an electronic service tool to clear the fault codes.

9. 9

   Perform a field test by toggling the machine from on-road to off-road mode. This will force the steering valve controller to run the spool movement test again and verify the repair.