Case IH 629-02 - UCM – UCM: Vehicle controller loss of communication with steering valve controller

The main vehicle controller has lost CAN bus communication with the Steering Valve Controller (SVC). This is typically caused by the CAN bus going offline, an open or short circuit on the communication wires, a loss of power/ground to the module, or a software initialization failure.

• MAGNUM AFS Connect
• AFS Connect Magnum Tractors 180, 200, 220, 240, 250, 280, 310, 340, 380
• Vestrum CVX Series Tractors 100, 110, 120, 130
• Axial-Flow Midrange Combines 5140, 6140, 7140, 5150, 6150, 7150

1. 1

   Check for an open circuit or short circuit on the CAN communication wires between the UCM and the Steering Valve Controller

2. 2

   Check for an open or short circuit on either the power supply or ground circuits feeding the Steering Valve Controller

3. 3

   Verify if the Steering Valve Controller has experienced a software initialization failure, an I2C communication failure, or if it is running outdated software

1. 1

   Hard Reset / Reseat Connectors

   Disconnect the wiring harness connectors from both the UCM and the Steering Valve Controller. Wait at least 30 seconds, then reconnect the connectors to ensure all pins are seated securely and free of corrosion.

2. 2

   Harness Repair

   If the diagnostic checks reveal a short to ground, short to voltage, or an open circuit on the CAN bus or power supply lines, repair or replace the affected section of the wiring harness.

3. 3

   Software Flash

   Reprogram the controllers with the latest OEM software. For example, AFS Connect Magnum tractors may require the Steering Valve Controller (SVC) and Steering Redundant Controller (SRC) to be flashed to software version 2.02, and the UCM updated to version 15.2.0.0 (or 1.17.0.0 for combines).

4. 4

   Component Replacement

   If the wiring is intact and the software flash does not resolve the communication failure, the Steering Valve Controller or the UCM has suffered an internal hardware failure and must be replaced.