Case IH 5391 – UCM: EHF Solenoids Return OC

The control module has detected an open circuit (a break in the electrical path) on the return (ground) circuit for the EHF directional control solenoids. This prevents the solenoids from completing their electrical circuit, meaning the Enhanced High-Flow (EHF) auxiliary hydraulics or proportional pump controls will fail to operate properly.

• skid steer
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• SV300
• SR270
• TR320
• TV380

1. 1

   Visually inspect the EHF solenoids on the main hydraulic pump/control valve block and the wiring harness routing from the UCM to the solenoids for chafing, pinching, or severed wires.

2. 2

   Disconnect the EHF solenoid connectors and the UCM harness connectors to check for pushed-out pins, corrosion, water intrusion, or loose terminals.

3. 3

   Measure the resistance of the EHF solenoid coils to verify they are not internally open.

4. 4

   Perform a continuity test on the return wire from the solenoid connector back to the UCM to isolate any break in the harness.

5. 5

   Turn the key ON and verify if supply voltage is reaching the solenoids to rule out a broader supply issue.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the negative battery cable to prevent electrical shorts during repair.

2. 2

   Access the Solenoids

   Tilt the cab or open the rear access panels as required by your specific skid steer/CTL model to access the hydrostatic/EHF pump assembly.

3. 3

   Repair Wiring

   If the diagnostic tests revealed a broken wire in the return circuit, splice and solder the wire, then seal it with heat-shrink tubing. If the connector is damaged, replace the pigtail connector.

4. 4

   Replace Solenoid

   If the solenoid coil tested 'open' internally, remove the retaining nut holding the solenoid coil to the valve stem. Slide the old coil off and install the new replacement coil. Torque the retaining nut to OEM specifications.

5. 5

   Reassembly and Testing

   Reconnect the wiring harness and the battery. Turn the key ON, clear the inactive fault codes using the instrument cluster or an electronic service tool (EST), and test the EHF auxiliary hydraulic functions to ensure the code does not return.