Case IH 15228 - AST – AST (Advanced Steering) Controller: AST: Cut-off solenoid supply voltage too high

The voltage being supplied to the cut-off solenoid within the Advanced Steering (AST) system is exceeding the expected parameters. This is typically caused by a short-to-power in the wiring harness, a faulty solenoid coil, or an internal failure within the steering controller outputting excessive voltage.

• MAXXUM T4E
• VESTRUM CVX
• Case IH Maxxum Series
• Case IH Puma Series
• Case IH Optum Series
• Case IH Farmall C Series (Tier 5 / Stage V)

1. 1

   Inspect the wiring harness between the AST steering controller and the steering valve's cut-off solenoid for chafed wires, melted insulation, or shorts to a 12V/24V power source.

2. 2

   Disconnect the cut-off solenoid and measure the supply voltage from the controller with the key ON to check for higher than specified system voltage.

3. 3

   Measure the resistance (ohms) across the cut-off solenoid pins to check for an internal short in the coil.

4. 4

   Use the tractor's instrument cluster (H menus, R1 module, menu H3) or Electronic Service Tool (EST) to read live values and actuate the spool movement test.

1. 1

   Disconnect Power

   Disconnect the tractor's battery to prevent electrical spikes during repair.

2. 2

   Repair Wiring

   If a short-to-power was found during the diagnostic phase, repair or replace the damaged section of the wiring harness.

3. 3

   Replace Solenoid

   If the wiring is intact but the cut-off solenoid failed testing, locate the steering valve block and remove the faulty cut-off solenoid. Install the new solenoid and torque to OEM specifications.

4. 4

   Reassemble and Clear Codes

   Reconnect the battery. Use the EST or the tractor's H-menu diagnostic interface to clear the 15228 fault code.

5. 5

   Recalibrate AST

   After replacing steering components or clearing AST faults, you must perform an AST Steering Calibration to ensure the main and safety controllers are synchronized.