Case IH 1955-03 - UCM – UCM: Rear pilot head #4 is reporting a supply voltage high

The electronic pilot head (the proportional actuator/solenoid assembly mounted on top of the hydraulic valve) for the #4 rear remote is receiving or reporting a voltage signal that exceeds the normal operating threshold (often indicating a short to a high voltage source or a system overcharge). The pilot head acts as the "brain" of the remote valve, controlling the precise hydraulic flow; when it detects a voltage anomaly, the system disables the valve to prevent erratic hydraulic movement or component damage.

• MAGNUM AFS Connect
• Magnum 180
• Magnum 190
• Magnum 200
• Magnum 210
• Magnum 220
• Magnum 225
• Magnum 240
• Magnum 250
• Magnum 280
• Magnum 310
• Magnum 340
• Magnum 380
• Puma 185
• Puma 200
• Puma 220
• Puma 240
• Steiger 350
• Steiger 400
• Steiger 450
• Steiger 500
• Steiger 550
• Steiger 580
• Steiger 600
• Quadtrac 350
• Quadtrac 400
• Quadtrac 450
• Quadtrac 500
• Quadtrac 550
• Quadtrac 580
• Quadtrac 600
• Optum 270
• Optum 300

1. 1

   Verify the tractor's alternator is not overcharging the entire system, which can trigger voltage high codes across multiple modules.

2. 2

   Inspect the wiring harness and connectors going to the #4 rear remote pilot head for chafing, corrosion, or pinched wires that could cause a short to battery voltage.

3. 3

   Perform a component swap test by swapping the electrical connection and/or the pilot head from the #4 remote with a known good remote (like #3). If the fault follows the pilot head, it has failed internally. If it remains on #4, the issue is in the harness or UCM.

4. 4

   Ensure the UCM is properly communicating with the valve and that the valve is addressed correctly on the CAN bus.

1. 1

   Relieve Pressure

   Turn off the tractor and relieve all hydraulic pressure from the system. Drain the hydraulic oil tank if required by the specific model's service manual.

2. 2

   Clean the Area

   Thoroughly clean the area around the #4 remote valve. Hydraulic pilot valves have extremely tight tolerances, and introducing dirt during installation will cause immediate failure.

3. 3

   Disconnect

   Unplug the electrical wire harness connection from the #4 pilot head solenoid.

4. 4

   Remove the Pilot Head

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

5. 5

   Install the New Part

   Place the new pilot head onto the valve body, ensuring all O-rings and seals are perfectly seated. Torque the mounting screws to the OEM specification.

6. 6

   Reconnect and Calibrate

   Reconnect the wiring harness. You must perform an EHR (Electro-Hydraulic Remote) calibration procedure using the tractor's display monitor or the CNH Electronic Service Tool (EST) so the UCM can learn the new pilot head's parameters.