Case IH tD3 – PCU (Powertrain Control Unit): Hand Throttle Position Sensor Potentiometer 2 Over Voltage

The control module is receiving a voltage signal from the second potentiometer circuit of the hand throttle that exceeds the normal operating parameters, typically caused by the sensor's signal wire shorting to a positive voltage source or an internal failure of the potentiometer's resistive track.

• MXM
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190
• Magnum
• Puma
• Steiger
• TM Series
• TM120
• TM190
• T6000
• T7000

1. 1

   Inspect the wiring harness running from the cab armrest/console to the PCU for chafing, pinching, or exposed wires that could cause a short to power

2. 2

   Disconnect the hand throttle position sensor and inspect the pins for corrosion, moisture, or loose terminals

3. 3

   Turn the key ON (engine off) and use a multimeter to verify that the sensor is receiving the correct reference voltage (typically 5V DC) and a solid ground

4. 4

   Back-probe the signal wire for Potentiometer 2 and slowly move the hand throttle from idle to full throttle. The voltage should scale smoothly. If it is stuck at a high voltage, the sensor is internally shorted or the wiring harness is shorted to power

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Access the Sensor

   Remove the trim panels on the right-hand armrest or side console to expose the hand throttle lever assembly.

3. 3

   Remove the Faulty Sensor

   Disconnect the electrical pigtail from the hand throttle potentiometer. Remove the mounting screws holding the potentiometer to the throttle lever mechanism.

4. 4

   Install the New Part

   Mount the replacement potentiometer, ensuring the mechanical linkage/tang aligns correctly with the throttle lever. Secure the screws and reconnect the wiring harness.

5. 5

   Reassemble

   Reinstall the console trim panels and reconnect the battery.

6. 6

   Perform Calibration

   Enter the H-Menu (Calibration Mode) on the tractor's digital display, navigate to the specific calibration mode for the hand throttle/transmission (often Mode HA), and follow the on-screen prompts to register the new minimum (idle) and maximum (full throttle) voltage values to the PCU.