Case IH 520206-25 - VCM – VCM (Vehicle Control Module): Steering valve controller roading switch disagreement

The steering valve controller is detecting an inconsistent state from the master roading switch (e.g., the switch position does not match the vehicle's operating state, or there is a physical circuit failure). When this disagreement occurs, the system may require steering calibrations or prevent the autoguidance system from engaging.

• MAGNUM AFS Connect
• Magnum AFS Connect Tractors (Models 180, 200, 220, 240, 250, 280, 310, 340, 380)
• Steiger Series Tractors (e.g., Steiger 620 Tier 4B)

1. 1

   Check Switch Position: Verify the physical position of the master roading switch (often located on the headliner or armrest). Ensure it is fully toggled into the "Field" position rather than stuck between modes or in the "On-Road" position.

2. 2

   Toggle Test: Manually toggle the roading switch back and forth. Often, cycling the switch will clear the disagreement error and allow the steering system to engage.

3. 3

   Harness and Connection Inspection: Inspect the wiring harness and connectors associated with the roading switch (such as the C656M hydraulic connector on Steiger models) for loose pins, corrosion, or harness failure.

4. 4

   CAN Communication Check: Verify that there are no CAN communication errors between the steering valve controller and the main vehicle controller, which can simulate a switch disagreement.

5. 5

   Software Verification: Check if the Steering Valve Controller (SVC) requires a software update (e.g., updating to software version 2.02) or if a steering calibration procedure needs to be performed to restore sensor plausibility.

1. 1

   Turn off the tractor and manually cycle the roading switch to ensure it is mechanically functioning and not physically jammed.

   Turn off the tractor and manually cycle the roading switch to ensure it is mechanically functioning and not physically jammed.

2. 2

   Access the back of the roading switch or the headliner panel to expose the switch wiring.

   Access the back of the roading switch or the headliner panel to expose the switch wiring.

3. 3

   Disconnect the roading switch and use a multimeter to test for proper continuity across the switch terminals in both the "Road" and "Field" positions.

   Disconnect the roading switch and use a multimeter to test for proper continuity across the switch terminals in both the "Road" and "Field" positions.

4. 4

   Inspect the female silver terminals (0.5 - 1.0 wire size) in the connector for spread pins or poor tension.

   Inspect the female silver terminals (0.5 - 1.0 wire size) in the connector for spread pins or poor tension.

5. 5

   If the switch fails the continuity test, replace the roading switch.

   If the switch fails the continuity test, replace the roading switch.

6. 6

   If the switch tests good, trace the harness back to the VCM/Steering Valve Controller to check for opens or shorts in the circuit.

   If the switch tests good, trace the harness back to the VCM/Steering Valve Controller to check for opens or shorts in the circuit.

7. 7

   Reconnect all components, power on the machine, and navigate to the ISOBUS diagnostic page on the display to verify the roading switch state is now reading correctly.

   Reconnect all components, power on the machine, and navigate to the ISOBUS diagnostic page on the display to verify the roading switch state is now reading correctly.

8. 8

   Perform a steering system calibration if prompted by the VCM, and clear the fault codes.

   Perform a steering system calibration if prompted by the VCM, and clear the fault codes.