Case IH 5111-09 - DEC – DEC: Rear differential lock control solenoid, electrical circuit fault, voltage above normal

The controller is detecting a short to a power source (12V) on the circuit that operates the rear differential lock solenoid.

• MAGNUM AFS Connect
• Steiger AFS Connect

1. 1

   Verify the exact fault text on the tractor's display to confirm it mentions the differential lock solenoid.

2. 2

   Visually inspect the rear differential lock solenoid on the rear axle/transmission housing, checking the wiring harness and 2-terminal connector for rubbed insulation, pinched wires, or moisture intrusion.

3. 3

   Disconnect the solenoid and use a multimeter to check the signal wire leading back to the DEC for a short to 12V (voltage above normal).

4. 4

   Measure the resistance across the differential lock solenoid coil to determine if it is internally shorted or out of specification.

1. 1

   Disconnect battery

   Turn off the tractor and disconnect the battery to prevent electrical spikes.

2. 2

   Repair wiring harness

   If the diagnostic tests reveal a short to power in the wiring harness, trace the harness back to the DEC and repair the damaged section of the wire.

3. 3

   Remove retaining hardware

   If the solenoid coil failed the resistance test, remove the retaining hardware holding the differential lock solenoid in place.

4. 4

   Remove faulty solenoid

   Remove the faulty solenoid valve from the transmission/axle housing.

5. 5

   Install new solenoid

   Lubricate the O-rings on the new solenoid with clean hydraulic oil and install it into the housing.

6. 6

   Torque retaining hardware

   Torque the retaining nut/hardware to OEM specifications.

7. 7

   Reconnect electrical harness

   Reconnect the electrical harness.

8. 8

   Clear fault code

   Reconnect the battery, power on the tractor, and use the EST (Electronic Service Tool) or the in-cab display to clear the fault code.

9. 9

   Test differential lock

   Test the rear differential lock engagement to ensure the code does not return.