Case IH 1979-11 - UCM – UCM: Rear pilot head #6 is reporting that the spool was not in neutral at power-on

When the tractor is keyed on, the system performs a safety check of the hydraulic remote valves. If the internal position sensor of the pilot head on remote valve #6 detects that the spool is shifted (not in the dead-center neutral position) during startup, it flags this code to prevent unintended hydraulic movement. In many cases, a shorted or internally failed pilot head will disrupt the CAN bus network, causing all rear remotes to go offline simultaneously.

• MAGNUM AFS Connect
• Magnum Series: 280, 310, etc.
• Steiger / Quadtrac Series: 350, 370, 400, 420, 450, 470, 500, 580
• Puma Series: 150, 165, 185, 200, 220, 240 (including CVT models)
• Optum Series: 270, 300
• Maxxum Series

1. 1

   Perform a CAN Bus Isolation Test: Unplug the electrical connector specifically at the #6 pilot head. If the rest of the remote valves immediately come back online, the #6 pilot head has suffered an internal electrical failure and must be replaced.

2. 2

   Inspect the wiring harness and connector at the #6 valve for corrosion, bent pins, or wire chafing that could be sending a false voltage signal to the UCM.

3. 3

   Clear the fault codes using the display or Electronic Service Tool (EST) and cycle the key to verify if the code is active or stored.

1. 1

   Depressurize

   Turn off the engine, cycle the key to the ON position (without starting), and actuate the hydraulic levers to relieve any trapped hydraulic pressure in the system. Turn the key OFF and disconnect the battery ground.

2. 2

   Locate the Valve

   Access the rear remote valve stack and identify valve slice #6.

3. 3

   Disconnect

   Unplug the electrical harness connector from the #6 pilot head.

4. 4

   Remove the Pilot Head

   Remove the mounting bolts securing the pilot head assembly to the main remote valve body. Carefully pull the pilot head away, ensuring no dirt enters the hydraulic system.

5. 5

   Install the New Part

   Lubricate the O-rings on the new pilot head valve assembly with clean hydraulic oil. Seat the new pilot head onto the valve body and torque the mounting bolts to OEM specifications.

6. 6

   Reconnect

   Plug the electrical harness back into the new pilot head.

7. 7

   Calibrate

   Reconnect the battery and power on the tractor. You must perform a remote valve calibration using the tractor's display monitor or the Case IH EST (Electronic Service Tool) so the UCM can learn the exact neutral position of the new spool.