Case IH 2012 - UCM – UCM: Clutch pedal potentiometer - voltage too high

The control module is receiving a voltage signal from the clutch pedal position sensor that exceeds the maximum expected threshold, typically caused by a short circuit to a power source, an open ground circuit in the sensor wiring harness, or an internal failure of the potentiometer itself.

• MAXXUM T4E
• VESTRUM CVX
• Puma 165
• Puma 180
• Puma 195
• Puma 210
• Puma 225
• Puma 240 CVT
• Magnum 7100
• Magnum 7200
• Magnum MX210
• Magnum MX230
• Magnum MX255
• Magnum MX285
• Farmall 40
• Farmall 45
• Farmall 50
• Farmall 105U
• Farmall 115U
• MXM series
• Maxxum series
• Steiger series
• Quadtrac series

1. 1

   Inspect the clutch pedal potentiometer (located at the pedal linkage) for physical damage, loose mounting hardware, or mechanical binding.

2. 2

   Inspect the transmission/chassis wiring harness for chafing, pinched wires, or disconnected terminals.

3. 3

   Using a multimeter, verify that the sensor is receiving the correct 5V reference voltage and has a solid ground connection (an open ground will cause the signal voltage to pull high).

4. 4

   Test the signal return wire to the UCM for a short to a 12V or 5V power source.

5. 5

   Test the internal resistance of the potentiometer while slowly depressing the clutch pedal to ensure resistance/voltage changes smoothly without spiking or dropping out.

1. 1

   Power Down

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

2. 2

   Access the Sensor

   Locate the clutch pedal potentiometer at the base of the clutch pedal assembly in the cab.

3. 3

   Disconnect

   Unplug the electrical harness connector from the potentiometer.

4. 4

   Removal

   Remove the retaining pins/screws securing the potentiometer to the pedal linkage and remove the faulty unit.

5. 5

   Installation

   Install the new OEM clutch pedal potentiometer and secure the mounting hardware.

6. 6

   Reconnect

   Plug the electrical harness back into the sensor and reconnect the battery.

7. 7

   Calibration

   Perform a transmission/clutch calibration procedure using the tractor's diagnostic interface, as replacing the sensor will often trigger fault code 2024 until the UCM relearns the new parameters.