Case IH 629-19 - UCM – Universal Control Module (UCM): Vehicle controller communication fault with the steering valve controller (SVC)

The Universal Control Module (UCM) is reporting a vehicle controller communication fault with the steering valve controller (SVC). This means the UCM is either not receiving CAN bus messages from the steering valve controller, or the data packets it is receiving are corrupted/invalid.

• MAGNUM AFS Connect
• AFS Connect Magnum Tractors (Models 180, 200, 220, 240, 250, 280, 310, 340, 380)
• Puma Series Tractors (Models 140, 150, 165, 175, 180)
• Vestrum CVX Series Tractors (Models 100, 110, 120, 130)
• Optum Series Tractors
• Maxxum Series Tractors
• Terrus Series Tractors
• Axial-Flow Combines (Midrange 5140-7150 and Flagship 7230-9250)
• Early Riser Planters 2000 Series (2130, 2140, 2150, 2160)

1. 1

   Verify battery and charging system voltage (drops below 9.8V can cause modules to drop offline)

2. 2

   Measure terminating resistance across CAN High and CAN Low pins at the diagnostic port with battery disconnected (should be approximately 60 ohms)

3. 3

   Inspect the wiring harness running between the UCM and the Steering Valve Controller for chafing, pinched wires, or heat damage

4. 4

   Disconnect harnesses at both the UCM and the SVC and inspect for pushed-out pins, corrosion, or moisture intrusion

5. 5

   Connect the Case IH Electronic Service Tool (EST) to check if the Steering Valve Controller is visible on the network; if offline, check dedicated power and ground supply wires to the SVC connector

1. 1

   Power Down

   Turn the ignition key to the OFF position and disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Wiring Repair

   If the diagnostic checks revealed damaged CAN wiring (CAN High / CAN Low) or compromised power/ground wires to the SVC, repair the harness using OEM-approved splicing techniques.

3. 3

   Clean Connections

   If moisture or mild corrosion is found in the UCM or SVC connectors, clean the pins with electronic contact cleaner and apply dielectric grease before reconnecting.

4. 4

   Software Flash

   Reconnect the battery. If the wiring is intact but the fault persists, use the Case IH EST to re-flash or update the software on both the UCM and the Steering Valve Controller. (Note: OEM bulletins frequently resolve communication timing issues by updating the SVC to software version 2.02 or newer).

5. 5

   Component Replacement

   If the SVC has good power, good ground, intact CAN lines, but remains unresponsive to the EST or fails to hold software, the Steering Valve Controller has failed internally and must be replaced.

6. 6

   Calibration

   If the Steering Valve Controller is replaced, you must use the EST to perform a steering system calibration and input the Advanced Steering Configuration dataset before returning the machine to service.