Case IH 520207-02 - VCM – VCM: Steering valve controller roading switch circuit fault

The steering valve controller is receiving an erratic, intermittent, or incorrect voltage signal from the roading switch circuit, preventing the auto-guidance system from verifying whether the tractor is safe to steer autonomously.

• MAGNUM AFS Connect
• 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
• Steiger / Quadtrac / Rowtrac 335
• Steiger / Quadtrac / Rowtrac 350
• Steiger / Quadtrac / Rowtrac 385
• Steiger / Quadtrac / Rowtrac 400
• Steiger / Quadtrac / Rowtrac 435
• Steiger / Quadtrac / Rowtrac 450
• Steiger / Quadtrac / Rowtrac 485
• Steiger / Quadtrac / Rowtrac 535
• Steiger / Quadtrac / Rowtrac 620
• Vestrum CVX 100
• Vestrum CVX 110
• Vestrum CVX 120
• Vestrum CVX 130

1. 1

   Manually toggle the roading switch back and forth to ensure it isn't physically stuck between contacts

2. 2

   Check the ISOBUS diagnostic page on the AFS display; look for the steering readiness 'status cake' showing two orange pieces with an exclamation point

3. 3

   Inspect the Cab Main Wire Harness leading to the roading switch (e.g., connector C656M) for loose pins, corrosion, or chafing

1. 1

   Power Down

   Turn off the tractor and disconnect battery power to prevent module damage during electrical testing.

2. 2

   Access the Switch

   Remove the trim panel on the headliner or armrest to access the back of the roading switch.

3. 3

   Test the Switch Continuity

   Disconnect the switch from the harness (e.g., connector C656M). Use a multimeter to test the switch for continuity in both the 'Road' and 'Field' positions. If the multimeter shows an open circuit when closed, or erratic resistance values, the switch has failed internally and must be replaced.

4. 4

   Test the Harness

   If the switch tests good, check the wiring harness for continuity between the switch connector and the VCM/UCM pins. Repair any broken or shorted wires in the cab harness.

5. 5

   Reassemble and Calibrate

   Install the new switch or repaired harness. Power on the tractor.

6. 6

   Verify Operation

   Press the 'AUTO' button on the joystick or headliner for at least one full second. Verify that the steering 'status cake' on the display fills with 3 green pieces (or a full green circle with a swirl), confirming the steering valve controller is ready and the roading switch fault is cleared.