Case IH 5501 – UCM (Universal Control Module): Loader Arm Spool Sensor Open or Shorted To Ground

The control module has detected an electrical fault—either an open circuit (broken wire/disconnected plug) or a short to ground—in the circuit for the sensor that monitors the position of the loader arm's hydraulic spool valve.

• skid steer
• Case Alpha Series SR130
• Case Alpha Series SR150
• Case Alpha Series SR175
• Case Alpha Series SV185
• Case Alpha Series SR200
• Case Alpha Series SR220
• Case Alpha Series SR250
• Case Alpha Series SV250
• Case Alpha Series SV300
• Case Alpha Series TR270
• Case Alpha Series TR320
• Case Alpha Series TV380
• Compact Track Loaders (CTL)

1. 1

   Visually inspect the wiring harness and connectors running from the Loader Arm Spool Sensor (on the main hydraulic control valve block) to the UCM for chafed wires, corrosion, or loose/bent pins.

2. 2

   Perform a continuity test on the sensor circuit with the key switch OFF by disconnecting the wiring harness from the spool sensor and the UCM, and using a multi-meter and a jumper wire attached to the chassis (frame) ground to ensure there are no breaks in the wire.

3. 3

   Check the sensor's signal wire for a short to ground using a multi-meter. If the multi-meter shows continuity to ground where there shouldn't be, the harness is shorted.

1. 1

   Access the Control Valve

   Safely lower the loader arms (or secure them with approved cylinder locks if they must be raised for access), turn off the engine, and relieve hydraulic pressure. Locate the main hydraulic control valve block.

2. 2

   Harness Repair

   If the diagnostic checks revealed a damaged connector or a short/open in the wiring harness, repair the damaged section of the harness or replace the connector plug.

3. 3

   Sensor Replacement

   If the wiring harness tests perfectly fine, the spool position sensor itself has failed internally. Disconnect the electrical plug from the loader arm spool sensor, unthread/remove the faulty sensor from the control valve block, install the new spool position sensor, and reconnect the harness.

4. 4

   Clear and Verify

   Turn the machine on, clear the Diagnostic Trouble Code (DTC) via the instrument cluster or service tool, and operate the loader arm to verify that the code does not return and the loader responds correctly.