Case IH 520206-02 - VCM – VCM / SVC / UCM: Steering valve controller spool greater than setpoint

This fault indicates a circuit error (such as an open circuit, short to ground, or stuck switch) in the Roading Switch circuit. When the controller detects a fault in this circuit, it defaults to the safe state (On-Road mode) and locks out all autoguidance and electrohydraulic steering capabilities.

• MAGNUM AFS Connect
• Case IH AFS Connect Magnum (Models 180, 200, 220, 240, 250, 280, 310, 340, 380)
• Case IH AFS Connect Steiger / Quadtrac
• Case IH Optum (Tier 4B)

1. 1

   Verify the roading switch is not physically stuck or damaged by toggling it back and forth to see if the Pro 1200 display registers a change between On-Road and Off-Road modes.

2. 2

   Navigate to the ISOBUS diagnostic page on the Pro 1200 display and check the status cake icon to see if the roading switch is locked out or not reading.

3. 3

   Open the right-hand side electronics compartment and check the fuse panel for blown fuses related to the Autosteering CAN port.

4. 4

   Check the wiring harness directly behind the roading switch for loose, disconnected, or pinched wires.

5. 5

   Ensure the Wheel Angle Sensor and Advanced Steering Valve calibrations have not been lost, as a failed calibration can trigger steering lockout faults.

1. 1

   De-energize the System

   Turn off the tractor ignition and disconnect battery power to safely de-energize the steering valve sub-systems and the VCM/SVC.

2. 2

   Access the Switch

   Locate the roading switch panel (either on the headliner or the right-hand dummy switch console, depending on cab layout). Carefully pry out the switch holder to access the rear connections.

3. 3

   Disconnect and Inspect

   Unplug the electrical connector from the roading switch. Inspect the female terminals for corrosion, moisture, or pushed-out pins.

4. 4

   Test the Switch

   Using a multimeter, test the roading switch for continuity across its pins in both the engaged and disengaged positions. If the switch fails to show proper continuity or is internally shorted, it must be replaced.

5. 5

   Test the Harness

   If the switch tests good, use a multimeter to check the harness from the switch connector to the Steering Valve Controller for continuity, shorts to ground, and shorts to power. Repair any damaged wiring.

6. 6

   Reassembly

   Install the new or tested roading switch (ensure the steering wheel icon is oriented correctly). Reconnect the harness and snap the switch panel back into place.

7. 7

   System Reset

   Reconnect battery power and turn the ignition ON. Toggle the switch to the "Off-Road" position and verify on the Pro 1200 display that the steering mode updates successfully.

8. 8

   Clear Codes

   Clear the inactive fault codes using the display diagnostic menu or the dealer Electronic Service Tool (EST).