Case IH 1955-00 - UCM – UCM: Rear pilot head #4 actuator temperature high

The electronic actuator (pilot head) that controls the #4 rear electro-hydraulic remote (EHR) valve is reporting an internal temperature that exceeds the maximum safe operating limit. This can be caused by an internal electrical short, a faulty temperature sensor, mechanical binding, or a wiring harness issue.

• MAGNUM AFS Connect
• Steiger AFS Connect
• Puma CVXDrive

1. 1

   Verify the tractor's overall hydraulic fluid level and temperature to rule out a system-wide overheating issue.

2. 2

   Inspect the wiring harness and connector at the #4 rear remote pilot head for melted wires, corrosion, or short circuits.

3. 3

   Swap the #4 pilot head actuator with an adjacent known-good actuator (such as the #3 remote) to isolate the failure. If the fault follows the actuator, it has failed internally. If it remains on #4, suspect the wiring harness or UCM.

4. 4

   With the pilot head removed, check the #4 spool valve for mechanical binding or sticking, which can cause the actuator's solenoids to draw excessive current and overheat.

1. 1

   Relieve hydraulic pressure

   Park the tractor on a level surface, turn off the engine, and actuate the remote levers to relieve all hydraulic system pressure.

2. 2

   Clean valve block

   Thoroughly clean the exterior of the #4 rear remote valve block to prevent dirt from entering the hydraulic system.

3. 3

   Disconnect harness

   Disconnect the electrical harness connector from the #4 pilot head actuator.

4. 4

   Remove mounting screws

   Remove the mounting screws (typically M5 x 20mm hex socket screws) securing the pilot head to the main valve body.

5. 5

   Remove pilot head

   Carefully pull the pilot head assembly away from the valve body.

6. 6

   Clean mating surface

   Clean the mating surface on the valve body and ensure no old O-ring material is left behind.

7. 7

   Install new pilot head

   Install the new pilot head assembly, ensuring that the new O-rings/seals are properly seated to prevent leaks.

8. 8

   Install mounting screws

   Install the mounting screws and tighten them evenly to the OEM specified torque.

9. 9

   Reconnect harness

   Reconnect the electrical harness.

10. 10

    Perform calibration

    Turn on the tractor and access the diagnostic/calibration menu on the display. You must perform a remote valve calibration procedure (often found in the HK menu / Channel 1 for valve calibration) so the UCM can learn the electrical characteristics of the new pilot head.