Case IH 519081-06 - UCM – UCM: Rear Hitch Raise Solenoid Current High / Shorted to Ground

The system has detected an abnormally high current draw or a short-to-ground condition on the circuit controlling the rear hitch raise solenoid.

• MAGNUM AFS Connect
• Magnum AFS Connect series
• Magnum 180
• Magnum 200
• Magnum 250
• Magnum 400
• Steiger AFS Connect
• Puma series

1. 1

   Safely lower the rear hitch to the ground to relieve hydraulic pressure before working near the valve block.

2. 2

   Locate the rear hitch raise solenoid on the rear electro-hydraulic valve block and inspect the wiring harness leading from the UCM to the solenoid for chafing, melted insulation, or pinched wires that could be shorting to the chassis.

3. 3

   Disconnect the 2-pin connector at the solenoid and inspect the pins for corrosion, water ingress, or melting caused by high current.

4. 4

   Use a multimeter to measure the resistance across the pins of the solenoid coil. A reading of 0 ohms (a dead short) or significantly below OEM specification indicates failed internal coil windings.

5. 5

   With the solenoid disconnected, check the harness-side high-driver circuit for continuity to ground to test for a shorted wiring harness.

1. 1

   Disconnect battery

   Disconnect the tractor's battery to prevent accidental shorting or module damage during the repair.

2. 2

   Remove retaining nut

   If the diagnostic checks point to a failed solenoid coil (the most common cause of an internal short), remove the retaining nut at the end of the solenoid cartridge on the rear valve block.

3. 3

   Remove old solenoid coil

   Slide the old solenoid coil off the valve stem. (Note: If the entire cartridge valve is physically damaged and needs replacement, unscrew it from the valve block, being prepared to catch a small amount of hydraulic fluid).

4. 4

   Repair electrical connector

   If the electrical connector is melted or damaged from the high current, cut back the damaged wire. Crimp on new terminals, insert them into a new connector housing, and secure them with a new locking wedge.

5. 5

   Install new solenoid coil

   Slide the new solenoid coil onto the valve stem and secure it with the retaining nut.

6. 6

   Reconnect harness

   Reconnect the electrical harness to the solenoid.

7. 7

   Reconnect battery

   Reconnect the battery and start the tractor.

8. 8

   Perform Hitch Calibration

   Access the tractor's Pro 700 / AFS Pro 1200 display monitor and perform a "Hitch Cal" (Hitch Calibration) procedure. This is required so the UCM can learn the electrical threshold limits of the new raise valve.

9. 9

   Clear fault codes

   Clear the inactive fault codes and verify proper rear hitch operation.