Case IH 15266 - AST – AST: Steering valve controller failure

The over-voltage supervisor synchronization between the main and safety controllers within the steering valve has failed, preventing the auto-guidance/steering system from operating safely.

• MAXXUM T4E
• VESTRUM CVX
• AFS Connect Magnum Series
• Vestrum CVX Series
• Farmall / Quantum F, N, V, CL Series
• Puma
• Optum/Terrus

1. 1

   Access On-Board Diagnostics by navigating the 'H' menus using the switches on the instrument cluster (R1 module, menu H3, select AST system and press the dimming key to accept) to view active subsystem states

2. 2

   Verify the software versions of the Steering Valve Controller (SVC) and Steering Redundant Controller (SRC) to see if an update (e.g., version 2.02) is needed

3. 3

   Test the machine's charging system and the specific wiring harness supplying power to the AST steering valve to ensure the alternator or voltage regulator is not sending voltage spikes to the controller

1. 1

   Resolve over-voltage conditions

   Resolve any underlying machine over-voltage conditions (e.g., faulty alternator regulator) if external voltage spikes are detected.

2. 2

   Re-flash controllers

   If the voltage supply is stable, re-flash the Steering Valve Controller (SVC) and Steering Redundant Controller (SRC) with the latest OEM software dataset.

3. 3

   Replace steering valve controller

   If a software update does not resolve the internal synchronization failure, the steering valve controller unit must be replaced.

4. 4

   Perform calibrations

   After replacement or reprogramming, perform a mandatory steering valve calibration and wheel rotational angle sensor calibration using the Case IH diagnostic tool (or compatible systems like the XSC C-Box steering control system).