Case IH 4372 – UCM (Universal Control Module): Reverse Pump Control Valves (Directional) Solenoid Left (B) Supply Shorted To Ground

The electrical supply circuit providing voltage to the left directional solenoid (Solenoid B) on the reverse pump control valve has a direct short to the chassis ground. Because the current is bypassing the solenoid coil and grounding out, the controller cannot actuate the valve, resulting in a loss of directional ground drive control.

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

1. 1

   Visually inspect the wiring harness from the UCM to the hydrostatic drive pump's directional control valves for chafing, pinched wires, or melted insulation

2. 2

   Isolate the circuit by disconnecting the electrical connector at the Left (B) Reverse Pump Control Valve Solenoid

3. 3

   Test the solenoid for an internal short by using a multimeter to measure resistance between the solenoid's power terminal and its metal housing (ground)

4. 4

   Test the wiring harness for a short by checking the supply wire for continuity to ground (with the UCM and solenoid disconnected)

5. 5

   Perform a solenoid click test using the Case IH Electronic Service Tool (EST) to verify if the UCM is sending the correct current to the valve

1. 1

   Power Down

   Turn off the machine and disconnect the negative battery cable to prevent further damage to the UCM.

2. 2

   Access the Pump

   Lift and mechanically lock the cab (on SSL/CTL models) or remove the necessary access panels to reach the hydrostatic drive pump assembly.

3. 3

   Address Wiring Shorts

   If the diagnostic checks revealed a harness short, open the protective loom at the damaged section. Cut out the exposed/shorted wire, splice in a new section using solder and dual-wall heat shrink tubing, and re-loom the harness. Secure it away from vibration points.

4. 4

   Replace the Solenoid

   If the solenoid coil is internally shorted, clean the area around the directional control valve to prevent hydraulic contamination. Remove the retaining nut holding the solenoid coil to the valve stem. Slide the old coil off, install the new solenoid coil, and torque the retaining nut to OEM specifications.

5. 5

   Reassembly and Clearing Codes

   Reconnect the solenoid electrical connector and the battery. Turn the key on and use the Case IH EST or the in-cab display to clear the inactive 4372 fault code. Test the machine's ground drive in reverse to confirm the repair.