Case IH 1931-04 - UCM – UCM: Rear pilot head #2 reporting supply voltage low

Specific code 1931-04 is undocumented in searched literature. UCM codes in the 1900-range typically indicate power supply or sensor reference voltage issues. FMI 04 translates to Voltage Below Normal, or Shorted to Low Source.

• MAGNUM AFS Connect
• MX Magnum tractors
• high-speed planters

1. 1

   Verify if the error code is currently active using the electronic maintenance tool.

2. 2

   Check the wiring harnesses and connectors between the UCM and the affected sensor/valve for physical damage, corrosion, or moisture.

3. 3

   Measure the voltage at the sensor/component pins to verify if it is receiving the correct reference voltage (e.g., checking if voltage is dropping below the 4.8V threshold on a 5V circuit).