Case IH 1967-03 - UCM – UCM: Rear pilot head #5 Voltage Above Normal, or Shorted to High Source

The control module is receiving a voltage signal from the component's circuit that exceeds the maximum expected operational limit. This is typically caused by a wire shorting directly to battery power, a loss of ground, or an internal short within the sensor/component itself.

• MAGNUM AFS Connect

1. 1

   Disconnect the "Rear pilot head #5" component and check if the voltage on the signal wire drops. If it does, the component is internally shorted.

2. 2

   Inspect the wiring harness between the UCM and the component for chafing, melted insulation, or areas where the signal wire may be shorting to a 12V power supply wire.

3. 3

   Check the UCM connectors and the component connectors for corrosion, bent pins, or water intrusion that could bridge power to the signal circuit.

4. 4

   Verify the UCM's own power supply voltages, as UCM supply voltage spikes (e.g., Fault 1901 - UCM Supply Voltage High) can sometimes cause cascading sensor voltage faults.

1. 1

   Repair or replace wiring

   Repairing or replacing the section of the wiring harness where the short to power is located.

2. 2

   Replace component

   Replacing the "Rear pilot head #5" component if it is found to be internally shorted.

3. 3

   Clear fault code

   Reconnecting all harnesses and using the Case IH EST (Electronic Service Tool) to clear the fault code and verify the repair.