Case IH 520205-23 - VCM – VCM / UCM: Steering valve controller steering sensor disagreement

This fault code indicates a plausibility error or signal mismatch between the steering valve controller and the steering angle sensor (wheel position sensor). The controller is detecting that the physical steering angle reported by the sensor does not match the expected position based on the hydraulic commands sent to the steering valve, or there is a discrepancy between redundant sensor signals.

• MAGNUM AFS Connect
• Magnum 250
• Magnum 280
• Magnum 310
• Magnum 340
• Magnum 380
• Magnum 400
• Steiger 370
• Steiger 420
• Steiger 470
• Steiger 500
• Steiger 540
• Steiger 580
• Steiger 620
• Quadtrac 370
• Quadtrac 420
• Quadtrac 470
• Quadtrac 500
• Quadtrac 540
• Quadtrac 580
• Quadtrac 620
• Optum 270 CVT
• Optum 300 CVT

1. 1

   Inspect the steering angle sensor mounted on the steering cylinder or front axle (or articulation joint) for physical damage to the sensor linkage, loose mounting brackets, or bent rods.

2. 2

   Disconnect the steering sensor harness and inspect the pins for corrosion, moisture intrusion, or pushed-back pins. Check the wiring harness routing for chafing or shorts to ground.

3. 3

   Ensure there is no excessive mechanical slack in the steering cylinder pins or tie rods. Verify that there are no internal hydraulic leaks in the steering cylinder that could cause the wheels to drift.

4. 4

   Attempt a steering angle sensor calibration using the Case IH Electronic Service Tool (EST) or the in-cab AFS display. If the sensor has drifted out of calibration, this may clear the code.

1. 1

   Park the tractor on a flat, level surface and ensure the wheels are pointed as straight as possible. Turn off the engine and remove the key.

   Ensure the wheels are pointed as straight as possible.

2. 2

   Locate the steering angle sensor on the steering cylinder/axle.

3. 3

   Disconnect the electrical harness connector from the sensor.

4. 4

   Remove the linkage connecting the sensor arm to the steering cylinder (if applicable).

5. 5

   Remove the mounting bolts/set screws holding the sensor body in place and carefully extract the old sensor.

6. 6

   Install the new steering angle sensor.

   Important: Ensure the alignment marks on the new sensor are properly indexed according to the wheels' straight-ahead position before tightening the mounting hardware.

7. 7

   Reattach the mechanical linkage and plug in the electrical connector.

8. 8

   Start the tractor.

   Keep clear of the wheels, as the steering may jerk or move suddenly as the controller reads the new uncalibrated sensor.

9. 9

   Perform the mandatory Steering Angle Sensor Calibration procedure using the tractor's display monitor or the dealer EST laptop to sync the new sensor's voltage sweeps with the VCM/UCM.

10. 10

    Test drive the tractor and engage the auto-guidance system to verify the fault code 520205-23 does not return.