Case IH 15314 - AST – Steering Valve Controller (SVC): Steering valve controller failure - Invalid SVC PWM calibration values

This code indicates that the Pulse Width Modulation (PWM) calibration values stored for the steering valve are invalid, missing, or out of acceptable range. When these values are invalid, the controller cannot safely or accurately actuate the steering valve, typically disabling auto-steer functions.

• MAXXUM T4E
• VESTRUM CVX
• Farmall 40
• Farmall 45
• Farmall 50
• Farmall 115U
• Vestrum CVX 100
• Vestrum CVX 110
• Vestrum CVX 120
• Vestrum CVX 130
• AFS Connect Magnum 180
• AFS Connect Magnum 200
• AFS Connect Magnum 220
• AFS Connect Magnum 240
• AFS Connect Magnum 250
• AFS Connect Magnum 280
• AFS Connect Magnum 310
• AFS Connect Magnum 340
• AFS Connect Magnum 380

1. 1

   Check for accompanying SVC codes such as 15312, 15317, or 15319 which might indicate a wiring or sensor voltage issue rather than a pure calibration loss

2. 2

   Inspect the wiring harness and connections between the Steering Valve Controller and the steering valve solenoids for corrosion, moisture, or backed-out pins

3. 3

   Verify the current software version on the SVC, as software corruption or outdated firmware can cause calibration values to drop or become invalid

1. 1

   Connect Diagnostic Tool

   Connect the CNH Electronic Service Tool (EST) to the machine's diagnostic port.

2. 2

   Perform Auto-Calibration

   Navigate to the steering/AST configuration menu and initiate the Steering Valve Auto-Calibration procedure. Follow the on-screen prompts to sweep the steering and allow the controller to relearn the correct PWM values.

3. 3

   Update Software

   If the calibration fails to complete or the code returns immediately upon key cycle, re-flash the Steering Valve Controller with the latest software (e.g., software version 2.02 for Magnum models).

4. 4

   Re-Calibrate

   After any software update, perform the steering valve calibration again.

5. 5

   Replace the Controller

   If the SVC refuses to accept or store the PWM calibration values after a software flash and wiring verification, the internal memory of the Steering Valve Controller has likely failed, and the module must be replaced.