Case IH 519072-03 - UCM – UCM: Rear hitch left draft sensor voltage high

The FMI 03 designation indicates "Voltage Above Normal, or Shorted to High Source." The control module is receiving a signal voltage from the left lower link draft sensor (load pin) that exceeds the maximum normal operating threshold (typically >4.5V on a 5V reference circuit). This usually indicates an open ground circuit, a short to power on the signal wire, or an internally shorted/failed draft sensor. When this occurs, the electronic draft control (EDC) system will typically disable automatic draft modes, though manual position control may still function.

• MAGNUM AFS Connect
• Magnum 215
• Magnum 235
• Magnum 245
• Magnum 250
• Magnum 275
• Magnum 280
• Magnum 290
• Magnum 305
• Magnum 310
• Magnum 315
• Magnum 335
• Magnum 340
• MX Magnum Series (MX180 through MX275)
• Puma 185
• Puma 230

1. 1

   Inspect the wiring harness and the connector at the left rear draft sensor pin (located at the chassis pivot point of the left lower lift arm) for torn wires, packed dirt, or corrosion.

2. 2

   Disconnect the sensor and turn the key ON. Verify you have a steady 5V reference signal and a solid ground at the harness connector. An open ground will cause the signal voltage to float high, triggering this code.

3. 3

   Swap the electrical connections between the left and right draft sensors. If the fault code changes to the right draft sensor, the sensor itself has failed. If the fault code remains on the left draft sensor, the issue is in the tractor's wiring harness or the UCM.

1. 1

   Preparation

   Lower the 3-point hitch completely to the ground to remove all physical load and tension from the lower lift arms. Turn off the tractor and disconnect the battery.

2. 2

   Disconnect

   Unplug the triangular or standard electrical connector from the left draft sensor pin.

3. 3

   Removal

   Remove the retaining bolt/hardware that secures the draft pin to the tractor chassis and lower link arm.

4. 4

   Extraction

   Slide the faulty draft sensor pin out of the linkage. (You may need to gently tap it out with a brass punch if it is seized with rust or dirt).

5. 5

   Installation

   Clean the bore, apply a light coat of anti-seize if recommended by the manual, and slide the new draft sensor pin into place. Secure it with the retaining hardware.

6. 6

   Reconnection

   Plug the electrical connector back in and reconnect the battery.

7. 7

   Calibration

   You must perform a rear hitch calibration via the tractor's display monitor or armrest controls. This allows the UCM to learn the new sensor's zero-load baseline and maximum span values. If calibration is not performed, the hitch will not lift evenly or draft correctly.