Case IH 517761-04 - UCM – UCM: Electro-hydraulic backup steering pressure sensor voltage low

The signal voltage returning from the backup steering pressure sensor has dropped below the minimum acceptable threshold, indicating a potential short to ground, an open circuit, or a failed sensor.

• MAGNUM AFS Connect
• Magnum 400 AFS Connect

1. 1

   Use the electronic service tool (EST) to confirm the fault code is currently active.

2. 2

   Check the wiring harness and connectors leading to the backup steering pressure sensor for physical damage, corrosion, or backed-out pins.

3. 3

   Measure the sensor supply voltage at the connector to verify the UCM is supplying a 5V reference (between 4.8 V and 5.2 V). A reading outside this range indicates a wiring issue or a UCM fault.

4. 4

   If the reference voltage and ground are good, test the sensor itself as it is likely internally shorted and causing the low voltage reading.

1. 1

   Repair wiring

   Repair any damaged wiring or replace the faulty connector pigtail if a short/open is found.

2. 2

   Replace sensor

   Replace the electro-hydraulic backup steering pressure sensor if it has failed internally.

3. 3

   Clear fault codes

   Reconnect the harness, turn the ignition key ON, and use the electronic maintenance tool to clear the fault codes and verify the machine can return to service.