Case IH 520201-19 - VCM – VCM: Loss of communication between the steering valve controller and the vehicle controller

The tractor's main computer has lost its CAN bus data link with the electrohydraulic steering valve actuator, which is responsible for automated steering (AccuGuide/GPS) and variable ratio manual steering.

• MAGNUM AFS Connect
• Case IH Magnum AFS Connect (Models 180, 200, 220, 240, 250, 280, 310, 340, 380, 400)
• Case IH Steiger AFS Connect
• Case IH Optum / Puma AFS Connect

1. 1

   Verify power supply to the steering controller (must be above 9V, ideally 12V+)

2. 2

   Observe diagnostic LEDs on the steering controller at startup (solid green top LED with others flashing indicates good communication; only top green LED indicates CAN failure)

3. 3

   Inspect CAN High and CAN Low wiring between the VCM and Steering Valve Controller for open circuits, shorts to ground, or corrosion at breakaway connectors

4. 4

   Check software versions on the VCM, Steering Valve Controller (SVC), and Steering Redundant Controller (SRC) for mismatches

1. 1

   Inspect and Clean Connections

   Locate the electrohydraulic steering valve (often a Danfoss OSPE or EHi unit). Disconnect the main harness to the PVED-CLS controller. Clean the pins with electrical contact cleaner and inspect for pushed-out pins or moisture intrusion.

2. 2

   Test CAN and Power

   Using a multimeter, probe the harness side of the steering valve connector. Verify you have steady battery voltage (above 9V, ideally 12V+) and good ground. Test the CAN bus resistance (should be approximately 60 ohms across CAN High and CAN Low with the battery disconnected).

3. 3

   Repair Wiring

   If voltage is low or CAN resistance is out of spec, trace the harness back to the UCM/VCM and repair any damaged wires or faulty relays supplying power to the steering circuit.

4. 4

   Replace the Controller

   If power, ground, and CAN integrity are verified but the UCM still cannot communicate with the steering valve, the PVED-CLS Steering Valve Controller has failed internally and must be replaced.

5. 5

   Reprogram and Calibrate

   After replacing the steering valve controller, you must use the Case IH Electronic Service Tool (EST) to flash the correct Advanced Steering Configuration dataset to the new module and perform a steering calibration.