Case IH 5602 – UCM (Universal Control Module / Utility Control Module): Loader Auxiliary Valve (Directional) Loader Auxiliary Solenoid(s) Shorted To Ground

The control module has detected that the electrical circuit supplying power to the directional solenoid(s) on the loader's auxiliary hydraulic valve has a short to ground. The voltage is finding a premature path to the machine's chassis/ground before completing its intended circuit through the solenoid coil, which will disable the auxiliary hydraulic functions and trigger a warning.

• skid steer
• Compact Track Loaders (CTL)
• SR series
• SV series
• TR series
• Puma
• Magnum
• Steiger
• Maxxum
• Farmall

1. 1

   Visually inspect the wiring harness from the UCM to the loader auxiliary valve block for pinched wires, chafing against the metal chassis, or melted insulation.

2. 2

   Disconnect the harness at the auxiliary solenoid and inspect the pins for corrosion, moisture ingress, or bent terminals that could bridge power and ground.

3. 3

   With the solenoid disconnected and machine off, use a multimeter to measure resistance between the solenoid supply wire on the harness side and chassis ground. Continuity indicates a harness short.

4. 4

   Measure the internal resistance of the auxiliary solenoid coil itself. Resistance at or near zero ohms to the solenoid casing indicates an internal short to ground.

1. 1

   Safety First

   Turn off the machine, lower the loader arms to the ground, relieve hydraulic pressure, and disconnect the negative battery terminal to prevent electrical spikes.

2. 2

   Locate the Valve

   Access the loader auxiliary control valve block (location varies by machine; on skid steers, it is typically under the cab; on tractors, it is often mid-mount on the right side).

3. 3

   Address Wiring

   If the diagnostic tests revealed a harness short, splice and repair the damaged section of the wire using weather-sealed heat-shrink connectors, or replace the affected harness section. Route the harness away from pinch points.

4. 4

   Replace the Solenoid

   Disconnect the electrical connector from the shorted auxiliary directional solenoid. Remove the retaining nut at the end of the solenoid stem. Slide the faulty solenoid coil off the valve cartridge. Slide the new OEM solenoid coil onto the stem and torque the retaining nut to OEM specifications (do not overtighten, as this can distort the spool).

5. 5

   Reassembly

   Reconnect the electrical connector to the solenoid.

6. 6

   Clear Codes

   Reconnect the battery and turn the ignition on. Use the CNH Electronic Service Tool (EST) to clear the UCM fault codes.

7. 7

   Operational Test

   Start the machine and test the auxiliary hydraulic functions to ensure the short is resolved and the valve operates smoothly.