Case IH 520227-25 - VCM – VCM: Steering valve controller steering wheel sensor disagreement

Fault code 520227-25 (FMI 25) indicates a signal crosscheck failed because the primary and redundant signals from the steering wheel angle sensor (SASA) deviate too much from each other, or there is a communication/transmit rate mismatch between the sensors and the controller.

• MAGNUM AFS Connect
• Case IH Magnum AFS Connect series
• Case IH Steiger AFS Connect series (e.g., Steiger 370, 420)
• Case IH Quadtrac AFS Connect series (e.g., Quadtrac 500)

1. 1

   Use a diagnostic tool to monitor the steering angle sensor (SASA) outputs. Check the deviation between the primary and redundant steering angle signals to confirm the mismatch.

2. 2

   Check the wiring harness and connections between the steering wheel sensor and the VCM/Steering Valve Controller. Look for open circuits, loose pins, or short circuits to +12V or ground.

3. 3

   Verify the transmit rate of the primary and redundant signals to ensure they are communicating properly on the CAN bus without timeouts.

4. 4

   Check for any related steering valve configuration errors (such as code 520224-25) that might indicate a software or setup issue rather than a hardware failure.

1. 1

   Inspect Connections

   Turn off the machine and physically inspect the wiring harness connecting the steering wheel angle sensor to the VCM. Clean any corroded connectors and repair any chafed wires.

2. 2

   Test the Sensor

   If the wiring is intact, evaluate the steering wheel angle sensor. If the primary and redundant signals show a high deviation that cannot be resolved by a system restart or recalibration, the sensor has suffered an internal failure.

3. 3

   Replace Components

   Replace the faulty steering wheel angle sensor (SASA). If the sensor is functioning correctly and the wiring is good, the fault lies within the VCM or the steering valve controller itself, which will need to be replaced.

4. 4

   Recalibrate

   After replacing the sensor, VCM, or steering valve controller, perform a factory reset and a full steering system/valve calibration so the new components are properly aligned and recognized by the VCM.