Case IH 701-04 - UCM – UCM: Scraper (auto aux) input 1 voltage low

The control module is detecting a voltage signal from the 'Scraper (auto aux) input 1' circuit that has dropped below the acceptable operational limit, typically pointing to an open circuit, a short to ground along the power supply to the controller, or a failed input device.

• MAGNUM AFS Connect
• Case IH Steiger Series (380, 430, 480, 530)
• Case IH Quadtrac / Rowtrac Series (470, 500, 540, 580, 620 Scraper models)
• Case IH Magnum Series

1. 1

   Test battery voltage to verify it is between 12 and 14 volts, as a generally low battery can trigger this fault.

2. 2

   Check system voltage at the main scraper wiring connector (often designated as C150 or C053 depending on the model).

3. 3

   Inspect connector cavities for bad connections, improper grounds, and test for a short to ground along the power supply line to the scraper controller.

4. 4

   Isolate the implement by turning the scraper control system OFF and disconnecting the scraper implement wiring from the tractor to determine if the short is on the tractor side or the implement side.

1. 1

   Disconnect Power

   Turn the key switch to the OFF position and disconnect the battery to prevent electrical damage during testing.

2. 2

   Disconnect Scraper Harness

   Disconnect the scraper wiring harness from the tractor's main receptacle (e.g., connector C150).

3. 3

   Trace the Input 1 Circuit

   Follow the scraper control manufacturer's troubleshooting guide to trace the 'Input 1' wire between the UCM and the auxiliary scraper control device.

4. 4

   Repair the Wiring/Connector

   If a short to ground or open circuit is found (commonly caused by pinched wires or corroded pins in the connector), splice and heat-shrink the damaged wire, or replace the damaged connector pins.

5. 5

   Clear the Fault

   Reconnect all harnesses. Turn the key switch to ON. Use the tractor's monitor (pressing the play/reset switch) or the Electronic Service Tool (EST) to clear the error icon and controller fault.

6. 6

   Test Operation

   Engage the AUTO AUX system (ensure PTO is OFF) and verify the monitor displays the correct status without triggering the voltage low alarm.