Case IH 5512 – UCM (Universal Control Module): Implausible Bucket Sensor State Vs Loader Bucket Command - Stuck Spool Or PRV

The control module is commanding the bucket spool to move (via the electro-hydraulic pilot system), but the bucket valve spool position sensor is reporting an implausible state (e.g., the spool is not moving as commanded, or it is moving when no command is present).

• skid steer
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• SR130
• SR150
• SR175
• SR200
• SR220
• SR250
• SV185
• SV250
• SV300
• TR270
• TR320
• TV380

1. 1

   Check the bucket valve spool position sensor (mounted on the loader control valve) for sticking, physical damage, or wiring issues (most common cause)

2. 2

   Inspect the wiring harness connecting the UCM to the bucket spool sensor and the PRV solenoids for open circuits or shorts to ground/power

3. 3

   Check the main control valve bucket spool for physical binding, scoring, or debris contamination that would prevent it from shifting

4. 4

   Verify that the Pressure Reducing Valve (PRV) / pilot solenoids are receiving the correct reference signals and voltage from the UCM

1. 1

   Relieve Pressure

   Safely lower the loader arms and bucket to the ground. Turn off the engine and relieve all hydraulic system pressure before servicing the control valve.

2. 2

   Inspect/Replace the Sensor

   Locate the bucket valve spool position sensor on the main loader control valve. Remove the sensor and check for sticking or internal failure. If the sensor is sticking or fails electrical testing, replace it.

3. 3

   Inspect the PRV and Spool

   If the sensor is functioning correctly, remove the PRV (pilot solenoid) for the bucket circuit. Inspect the cartridge for debris or damaged O-rings.

4. 4

   Clean the Valve Body

   Carefully extract the bucket spool from the main control valve. Clean the spool and the valve bore. If the spool is physically stuck due to severe scoring or contamination, the main control valve assembly may need to be replaced.

5. 5

   Reassembly & Calibration

   Install the new sensor, PRV, or control valve. Restore hydraulic fluid levels and pressure. Clear the UCM fault codes using an Electronic Service Tool (EST) and verify that bucket rollback/dump functions operate at normal speeds without triggering the code.