Case IH 1991-19 - UCM – UCM: Rear pilot head #7 reporting communication fault with vehicle controller

The electronic pilot head mounted on top of the remote valve has suffered an internal controller failure or has lost CAN Bus communication with the main controller, which can take down the entire communication network.

• MAGNUM AFS Connect
• Magnum
• Steiger (Quadtrac)
• Maxxum
• Puma

1. 1

   Unplug the suspected faulty pilot head (#7) to isolate the CAN Bus. If the rest of the remote valves and network come back online, the pilot head itself is confirmed as the source of the failure.

2. 2

   Verify that the UCM is receiving proper voltage, as UCM power supply drops can trigger false communication faults across the network.

3. 3

   Connect the Case IH Electronic Service Tool (EST) to verify if the fault is intermittent or hard-set.

1. 1

   Remove the Faulty Pilot Head

   Disconnect the wiring harness from the faulty rear pilot head mounted on top of the remote valve body.

2. 2

   Install the New Pilot Head

   Mount the replacement pilot head to the valve body.

3. 3

   Reassign the Valves

   You must reassign the valves in the tractor's display/system in order to make the new pilot head communicate properly.

4. 4

   Calibrate the Valve

   A valve calibration is strictly required when installing a new valve pilot head. This is done via Channel 1 (Valve Calibration) on the tractor's diagnostic menu.

5. 5

   Attach Special Tools for Calibration

   The calibration process requires connecting a pressure transducer (Special Tool #380001903) and a jumper harness (Special Tool #84148258) to complete the onboard calibration of the rear EHR valves.