Case IH 7017 - UCM – UCM: Differential lock solenoid - open circuit

The control module has detected an open electrical circuit in the differential lock solenoid system. This means that electrical current is not flowing through the circuit, which is typically caused by a disconnected plug, a broken wire in the harness, or a burnt-out internal coil within the solenoid itself.

• MAXXUM T4E
• Puma 140
• Puma 150
• Puma 165
• Puma 180
• Puma 195
• Puma 210
• Puma 225
• Maxxum series
• Magnum series
• Steiger tractors

1. 1

   Visually inspect the differential lock solenoid (located on the rear axle housing or transmission valve block) and its electrical connector to ensure it is securely plugged in and free of dirt, water, or corrosion.

2. 2

   Inspect the wiring harness running from the UCM to the solenoid for physical damage, chafing, or broken wires.

3. 3

   Perform a continuity/resistance test by disconnecting the solenoid plug and using a digital multimeter to measure resistance across the solenoid's pins. An 'OL' (open line) or infinite resistance reading indicates a broken internal coil.

4. 4

   Perform a voltage test at the harness connector with the tractor key ON and the differential lock switch engaged to verify the UCM is sending the command signal.

1. 1

   Park and secure tractor

   Park the tractor on a level surface, engage the parking brake, and turn off the engine.

2. 2

   Clean area

   Clean the area around the differential lock solenoid to prevent dirt from entering the hydraulic system.

3. 3

   Disconnect harness

   Disconnect the electrical harness from the faulty solenoid.

4. 4

   Repair wiring harness

   If the issue was traced to a broken wire in the harness, splice and repair the wire using weather-sealed connectors, then clear the code.

5. 5

   Remove faulty solenoid coil

   If the solenoid coil failed the continuity test, remove the retaining nut holding the coil to the valve stem (or unscrew the entire cartridge valve, depending on the specific tractor model's valve block design).

6. 6

   Install new solenoid coil

   Slide the new solenoid coil onto the valve stem and secure it with the retaining nut, torquing to OEM specifications.

7. 7

   Reconnect harness

   Reconnect the electrical harness.

8. 8

   Clear fault codes

   Turn the key ON and use the tractor's diagnostic display to clear the fault codes.

9. 9

   Test operation

   Start the tractor and engage the differential lock to ensure the code does not return and the lock engages properly.