Case IH 2259-00 - UCM – UCM: Rear pilot head #8 actuator temperature high

The system has detected an abnormally high temperature in the electronic actuator (pilot head) that controls the spool movement for the #8 rear electro-hydraulic remote (EHR) valve. This typically indicates an internal electrical failure in the actuator causing it to overheat, excessive current draw due to a wiring short, or the actuator overworking due to a mechanically binding hydraulic spool.

• MAGNUM AFS Connect
• Magnum AFS Connect series
• Steiger AFS Connect series
• Puma CVX series (180-260)

1. 1

   Carefully check the physical temperature of the #8 rear remote pilot head (mounted on top/end of the valve section) to confirm if it is actually overheating or if the internal temperature sensor has failed.

2. 2

   Inspect the 4-pin electrical connector and wiring harness leading to the #8 pilot head for corrosion, melted insulation, or short circuits to ground that could cause high current draw.

3. 3

   Check for hydraulic system contamination and a worn or contaminated main spool in the valve body, which can cause the pilot head to work excessively hard to move the valve, leading to overheating.

4. 4

   Swap the #8 pilot head with a known good pilot head from another remote (e.g., #7). If the fault code changes to the new location (e.g., 1991-XX for pilot head #7), the pilot head itself is faulty. (Note: Swapping pilot heads usually requires reassigning the valves in the display monitor so the UCM recognizes the change).

1. 1

   Preparation

   Turn off the tractor, lower all implements, and relieve all hydraulic pressure from the rear remotes.

2. 2

   Disconnection

   Unplug the electrical connector from the #8 rear remote pilot head.

3. 3

   Removal

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

4. 4

   Extraction

   Carefully lift the faulty pilot head off the valve section. Ensure the O-rings are removed and the mating surface is clean.

5. 5

   Installation

   Lubricate the O-rings on the new pilot head with clean hydraulic oil. Seat the new pilot head assembly onto the valve body.

6. 6

   Torque

   Install and tighten the mounting screws to the specified torque (generally around 27-31 Nm / 19-22 lb-ft depending on the exact valve block).

7. 7

   Reconnection

   Plug the electrical connector back into the new actuator.

8. 8

   Calibration / Reassignment

   You must reassign and calibrate the new remote valve pilot head through the tractor's display monitor (often found in the "H menu") or by using the Case IH Electronic Service Tool (EST). If this is not done, the UCM will not recognize the new pilot head and will throw an offline/uncalibrated code.