Case IH 2387 - UCM – UCM: Shuttle lever neutral switch - voltage too low

The control module is receiving a voltage signal from the momentary shuttle lever's neutral switch that falls below the acceptable threshold. The underlying condition is typically an open circuit, a short to ground, a faulty connector, or a failed switch inside the shuttle lever assembly.

• MAXXUM T4E
• VESTRUM CVX
• Puma Series
• Puma 125
• Puma 140
• Puma 165
• Puma 180
• Puma 195
• Puma 210
• Puma 225
• Puma 240 CVT
• Farmall Series
• Farmall 95U
• Farmall 105U
• Farmall 115U Pro EP
• Maxxum Series
• Magnum Series

1. 1

   Verify if any other error codes are displayed. If no other codes are present, proceed with the diagnosis.

2. 2

   Check that the tractor battery has not been connected to an external power supply (like a jump starter or charger). If connected, disconnect it and test the system for normal operation.

3. 3

   Attempt a transmission re-enable test by depressing the clutch pedal or cycling the shuttle lever. If 'CP' (Clutch Position/Pedal) is no longer displayed on the dash, test for normal operation. If 'CP' remains, proceed to wiring checks.

4. 4

   Perform a switch operation/display test via the electronic module diagnostic menu (H5). Turn ignition ON, depress clutch, move shuttle lever, and watch channels d15, d16, d23, and d24. If the code does not display or the audible tone is not heard, perform a wiggle test on the wiring harness.

1. 1

   Inspect Wiring and Connectors

   Examine the wiring harness and the connector at the base of the shuttle lever for bent pins, corrosion, or broken wires. Repair any damaged wiring.

2. 2

   Replace the Shuttle Lever / Switch

   If the wiring and connectors are intact but the switch fails the diagnostic operation test, the momentary shuttle lever neutral switch (often integrated into the shuttle lever assembly) is faulty and must be replaced.

3. 3

   Check the UCM

   If the switch and harness both test good, the fault may lie within the Universal Control Module (UCM) itself, requiring module replacement.

4. 4

   Clear Codes and Test

   Once the physical repair is complete, clear the error code from the UCM memory.

5. 5

   Final Validation

   Cycle the tractor and test the power shuttle system in forward, neutral, and reverse to ensure normal operation.