Case IH 4062 – UCM (Universal Control Module): Forward Pump Control Valves (Directional) Solenoid Right (A) Supply Shorted To Ground

The control module has detected that the electrical supply circuit providing power to the right-side forward drive pump solenoid has a short to ground. The electrical current is finding a premature path to the machine's chassis or ground circuit, which prevents the solenoid from energizing. As a result, the machine will likely fail to drive forward on the right side.

• skid steer
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)

1. 1

   Visual Inspection: Trace the wiring harness from the UCM to the right-side hydrostatic pump control valve. Look for chafed wire insulation, pinched wires, or areas where the harness is rubbing against the metal chassis.

2. 2

   Harness Short Test: Disconnect the electrical connector at the Right (A) Solenoid and at the UCM. Use a digital multimeter to check for continuity between the solenoid supply wire and the machine ground. If continuity exists, the wiring harness is shorted.

3. 3

   Solenoid Coil Test: Check the resistance of the Right (A) Solenoid coil itself. Test for continuity between the solenoid's power pin and the solenoid's metal casing. If there is continuity, the solenoid is internally shorted to ground.

4. 4

   Connector Check: Inspect the UCM and solenoid connectors for water intrusion, corrosion, or bent pins that could be bridging the power supply to a ground pin.

1. 1

   Disconnect Power

   Turn off the machine, remove the key, and disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Access the Pump

   Tilt the cab or open the service access panels to reach the hydrostatic drive pumps.

3. 3

   Locate the Solenoid

   Identify the Forward Pump Control Valve on the right side of the pump assembly and locate Solenoid A (Right Forward).

4. 4

   Repair the Wiring (If Applicable)

   If the diagnostic checks revealed a short in the harness, cut out the damaged section of the wire. Splice in a new section of wire using environmentally sealed (heat-shrink) butt connectors. Wrap the repair in protective wire loom and secure it away from moving parts or sharp edges.

5. 5

   Replace the Solenoid (If Applicable)

   If the solenoid coil is internally shorted: Disconnect the wiring harness from the solenoid. Remove the retaining nut at the end of the valve stem. Slide the old solenoid coil off the valve cartridge. Slide the new OEM solenoid coil onto the stem and torque the retaining nut to the manufacturer's specification (do not overtighten, or you may distort the valve).

6. 6

   Reassembly

   Reconnect the electrical connector, ensuring the locking tab clicks and the weather seal is seated.

7. 7

   Test

   Reconnect the battery, start the machine, and clear the inactive codes. Test the forward drive function to ensure the code does not return.