Case IH 65 – Electronic Management Unit (EMU) / Tractor Controller Unit (TCU) / Hitch Controller: EDC Hydraulic Valve Lower Solenoid Short Circuit

The Electronic Draft Control (EDC) system uses this solenoid to actuate the hydraulic valve that lowers the rear three-point hitch. The fault is triggered when the controller detects an electrical short to ground, a short to 12V, or an open circuit in the lower solenoid's wiring or coil.

• JXC
• MXM
• Maxxum MXM 120
• Maxxum MXM 130
• Maxxum MXM 140
• Maxxum MXM 155
• Maxxum MXM 175
• Maxxum MXM 190
• Magnum 7100
• Magnum 7200
• Magnum 8900
• Magnum 235-340
• Puma Series
• Steiger Series

1. 1

   Visual & Harness Inspection: Check the wiring harness and connectors associated with the lower solenoid valve for damage, corrosion, or loose connections.

2. 2

   Resistance Test: Measure the resistance of the solenoid valve coil. A healthy coil typically reads between 3.8 to 4.2 Ohms. If the resistance falls outside these parameters or shows continuity to ground, the solenoid is shorted and must be replaced.

3. 3

   Hydraulic Bypass Test: Supply 12 volts directly to the power pin and ground the ground pin (do not ground directly to the control module). Stand clear of the hitch and start the engine. If the hitch lowers correctly, the valve and solenoid plunger are fine; the issue is in the tractor's wiring harness or the EMU. If the hitch does not lower, the solenoid plunger or hitch valve is mechanically failed.

1. 1

   Depressurize the System

   Ensure the tractor is turned off. Fully lower the rear hitch to the ground or mechanically support it to relieve all hydraulic pressure from the EDC circuit.

2. 2

   Locate the Valve

   Locate the EDC hydraulic control valve block, typically mounted at the rear of the tractor near the hitch assembly.

3. 3

   Disconnect Wiring

   Unplug the electrical connector from the lower solenoid.

4. 4

   Remove the Solenoid

   Remove the retaining nut/screws holding the solenoid manifold to the valve body.

5. 5

   Inspect the Plunger

   Remove the solenoid control unit and spring from the end of the manifold. Inspect the manifold, spring, and plunger for scoring, debris, or damage. If the plunger is stuck off-center to the left, it will cause the hitch to drift down.

6. 6

   Replace Component

   If the coil failed the resistance test, slide the new solenoid coil onto the valve stem.

7. 7

   Reassembly

   Reinstall the spring and secure the solenoid. Reconnect the electrical harness.

8. 8

   Calibration

   Clear the fault codes using the tractor's display monitor or an Electronic Service Tool (EST). You must perform a hitch calibration after replacing EDC components. Note: Engine speed must usually be set above 1600 RPM during the calibration of the lower valve.