Case IH 520202-19 - VCM – UCM: Communication loss between the steering valve controller and the auxiliary steering device

Indicates a failure on the CAN bus network (specifically J1939 protocol) where the steering valve controller is no longer receiving expected messages or signals from the auxiliary steering input (such as a joystick or mini-steering wheel).

• MAGNUM AFS Connect
• Case IH Magnum Series
• Case IH Steiger Series
• Case IH Vestrum CVX Series
• Case IH Axial-Flow Combines

1. 1

   Verify the integrity of the CAN bus (J1939) wiring between the UCM, the Steering Valve Controller (SVC), and the auxiliary steering device for open circuits, shorts to ground, or excessive bandwidth occupation

2. 2

   Check the DC power supply to the steering valve controller (12V/24V) to ensure stable voltage and good grounds

3. 3

   Ensure that the auxiliary steering device is properly configured in the software

4. 4

   Look for accompanying UCM codes such as 520202-02 or 520202-09 to help isolate the issue

1. 1

   Access the Diagnostic Display

   Use the AFS Pro display or electronic service tool to read the freeze-frame data associated with 520202-19 to see the exact conditions when the communication loss occurred.

2. 2

   Inspect Harnesses and Connectors

   Physically inspect the multi-pin OEM connectors at the UCM, the Steering Valve Controller (often a Danfoss PVED-CLS unit), and the auxiliary steering joystick/mini-wheel. Clean any corrosion and ensure pins are seated tightly.

3. 3

   Test Continuity

   Use a multimeter to test the CAN High and CAN Low lines between the auxiliary steering device and the steering valve controller. Repair any broken wires.

4. 4

   Software Update/Calibration

   If the wiring is intact, verify the software versions. (For example, the Steering Valve Controller (SVC) should be running software version 2.02). Recalibrate the steering system parameters via the service tool.

5. 5

   Component Replacement

   If communication cannot be restored and the wiring/software is verified good, the fault lies internally within either the auxiliary steering device, the Steering Valve Controller, or the UCM. Replace the faulty module and perform a mandatory steering calibration.