Case IH 2386 - UCM – UCM: Shuttle lever neutral switch - voltage too high

This code indicates that the control module is receiving a voltage signal from the forward/reverse shuttle lever's neutral switch that exceeds the maximum expected threshold. This typically points to a short to power in the wiring harness, a failed switch internally shorting, or an overcharging issue in the electrical system.

• MAXXUM T4E
• VESTRUM CVX
• Case IH Puma Series (e.g., Puma 165, 175, 210, 225)
• Case IH Magnum Series (e.g., MX210, MX230, MX255, MX285)

1. 1

   Verify the alternator/charging system is not overcharging and sending excessive voltage to the modules.

2. 2

   Ensure no external power supplies or jump-starters are improperly connected and feeding high voltage into the system.

3. 3

   Inspect the wiring harness between the shuttle lever and the UCM. Look for rubbed-through insulation causing a short to a 12V power source.

4. 4

   Test the shuttle lever neutral switch and related solenoids for internal shorts.

5. 5

   If the wiring and switch test fine, the Universal Control Module (UCM) itself may be faulty and misreading the voltage.

1. 1

   Disconnect Power

   Turn off the tractor and disconnect the battery to prevent electrical damage during testing.

2. 2

   Access the Shuttle Lever

   Remove the steering column/dash cowlings to access the base of the forward/reverse shuttle lever.

3. 3

   Inspect and Test Wiring

   Disconnect the shuttle lever harness. Using a multimeter, check the neutral switch signal wire for continuity to power (which would indicate a short).

4. 4

   Replace the Switch/Lever

   The neutral switch is typically integrated directly into the shuttle lever assembly. If the switch has failed and is sending high voltage, remove the mounting screws (usually M4 hardware) and disconnect the lever assembly. Install the new shuttle lever assembly.

5. 5

   Reassemble and Reconnect

   Reinstall the steering column cowlings and reconnect the battery.

6. 6

   Clear Codes

   Turn the key on. You must use the tractor's diagnostic menu or a service tool to clear the error code from the UCM.

7. 7

   Operational Test

   Test the system for normal operation by shifting the shuttle lever through Forward, Neutral, and Reverse to ensure the code does not return.