Case IH 520200-02 - VCM – VCM: Vehicle Speed Sensor Communication Failure

The steering valve controller has lost reliable CAN bus communication with the vehicle speed sensor, or the sensor is sending erratic, intermittent or invalid data.

• MAGNUM AFS Connect
• Case IH machines equipped with electro-hydraulic steering (EHPS), auto-guidance (AccuGuide), or Steer-by-Wire (SbW) systems

1. 1

   Verify that the Vehicle Speed Sensor is receiving proper power and ground

2. 2

   Inspect the wiring harness and connectors between the Vehicle Speed Sensor and the CAN bus for disconnected plugs, broken wires, or corrosion

3. 3

   Check for overall CAN bus disturbances or interference that might be corrupting the message timing or causing a sequence error

4. 4

   Verify the parameter setting of the VSP (Vehicle Speed Sensor) source address in the controller to ensure it hasn't been corrupted or incorrectly configured

1. 1

   Locate Components

   Locate the Vehicle Speed Sensor (usually on the transmission or wheel hub) and the Steering Valve Controller (VCM).

2. 2

   Inspect Wiring

   Carefully inspect the wiring harness connecting the speed sensor to the main CAN bus. Repair any chafed wires, bent connector pins, or corroded terminals.

3. 3

   Test Sensor Power

   Using a multimeter, confirm the sensor is receiving the correct reference voltage and ground. If power is missing, trace the circuit back to the fuse or power distribution module.

4. 4

   Replace Sensor

   If the wiring, power, and CAN connections are intact but the controller still reports erratic/missing data (FMI 2), the Vehicle Speed Sensor has likely failed internally and must be replaced.

5. 5

   Software/Calibration

   If the sensor is replaced and the code persists, connect the diagnostic tool to verify the CAN wheel angle/speed sensor calibration data and ensure the VSP source address parameters are correct.