Case IH 1919-04 - UCM – UCM: Rear pilot head #1 reporting supply voltage low

The microprocessor in the pilot head for remote #1 detects that its supply voltage has dropped below the acceptable operational limit, or the Universal Control Module (UCM) detects a short-to-ground on the sensor supply circuit feeding that pilot head.

• MAGNUM AFS Connect
• Case IH Magnum series
• 340 Magnum
• Case IH Maxxum series
• Maxxum 125
• Case IH Steiger
• Case IH Puma

1. 1

   Verify system voltage: Ensure the tractor's alternator is outputting correctly (13.8 to 14.4 volts) and the batteries are fully charged, as a general low-voltage condition can trigger UCM supply faults.

2. 2

   Check harness and connectors: Disconnect the harness at the rear remote #1 pilot head. Measure the voltage on the supply pin (typically 5V +/- 0.25V for sensor supply or 12V for solenoid supply). Check harness continuity to the UCM and ensure there is no short to ground.

3. 3

   Perform mechanical spool check: Remove the pilot head from the remote valve. Press on the end of the spool with your thumb. It should move freely within the bore and extend out slightly. If it binds, the issue is in the valve body, not the electronics.

4. 4

   Verify software levels: Ensure the most current software is downloaded into all remote valves. All pilot heads on the tractor must be at the same software level to function correctly.

1. 1

   Clear the Code

   Clear the active error code and test the system. If the fault code redisplays immediately, proceed to replacement.

2. 2

   Remove the Pilot Head

   Unplug the CAN/power connector from the rear remote #1 pilot head. Unbolt the pilot head from the main valve body.

3. 3

   Replace the Assembly

   Install the new pilot head. OEM Note: The pilot head contains an integrated microprocessor and sensors, and can only be serviced as a complete assembly. It cannot be rebuilt.

4. 4

   Recalibrate the Valve

   Once installed, you must calibrate the electro-hydraulic control valve. Navigate to the EHR CAL screen on the tractor's display (or use the electronic service tool). Select the desired remote valve and press the PROG key to start calibration. The display will indicate when the valve calibration is successful.