Case IH 1944-02 - UCM – UCM: Vehicle controller loss of communication with rear pilot head #3

The vehicle's controller has lost electrical or CAN bus communication with the 'pilot head' on the #3 rear remote valve. When this communication loss occurs, the system will typically lock up the affected remote valve (and sometimes all hydraulic functions) until the tractor is restarted.

• MAGNUM AFS Connect
• Magnum Series
• Steiger / Quadtrac Series
• Puma Series

1. 1

   Inspect the wiring harness between the front and rear halves of the tractor (especially on articulated models) for wires rubbed raw at the 'P' clamps.

2. 2

   Unplug and inspect connectors at the UCM and the #3 pilot head for water, dirt, or corrosion.

3. 3

   Verify that the UCM is outputting the correct voltage to the pilot head circuit (power/ground).

4. 4

   Use the Case IH Electronic Service Tool (EST) to check if the pilot head is reporting an internal controller fault.

1. 1

   Repair Wiring

   If the diagnostic checks reveal exposed wires at the articulation joint 'P' clamps or near the UCM connectors, repair the wiring harness and secure it to prevent future chafing.

2. 2

   Replace the Pilot Head

   If the wiring is intact, the pilot head itself has likely failed internally. Remove the faulty electronic pilot head from the top of the #3 remote valve body and install the replacement.

3. 3

   Reassign the Valve

   The new pilot head must be reassigned so the UCM knows which cab lever controls it.

4. 4

   Perform Calibration

   Access the tractor's 'H menu' (specifically the HK menu) via the display, navigate to Channel 1 (Ch 1), and follow the on-screen prompts to renumber the valves. Alternatively, this calibration procedure can be performed using the Case IH EST (Electronic Service Tool).