Case IH 143 – TRANS (Transmission): Front suspension position is above the upper suspension range

The front suspension position sensor (a potentiometer) is sending a voltage signal to the controller that exceeds the maximum expected limit for the suspension's upward travel. This can be caused by the suspension physically overextending, a sensor out of adjustment, a faulty sensor, or a wiring issue (such as a short to power).

• MX Magnum
• MX Magnum Series
• Magnum 275
• MX210
• MX230
• MX255
• MX285
• TG Series
• TG210
• TG230
• TG255
• TG285

1. 1

   Locate the front suspension position sensor (potentiometer), which is typically located under the front left side of the tractor.

2. 2

   Perform a voltage test on the sensor's output using a voltmeter; the voltage should change smoothly as the suspension moves and should not be stuck high or read out of range.

3. 3

   Verify the readings of the rod-side and piston-side suspension pressure transducers, as faulty pressure sensors can cause erratic suspension behavior and prevent calibration.

4. 4

   Inspect the wiring harness leading to the position sensor for any shorts to power (+12V or 5V reference) or open circuits.

1. 1

   Preparation

   Park the tractor on a level surface, engage the parking brake, and safely support the front chassis if the suspension needs to be depressurized.

2. 2

   Access the Sensor

   Navigate to the front left of the tractor to access the front suspension position potentiometer.

3. 3

   Removal

   Disconnect the electrical connector from the sensor. Unbolt the sensor from its mounting bracket and disconnect it from the suspension linkage.

4. 4

   Installation

   Install the new position sensor and reconnect the physical linkage.

5. 5

   Adjustment

   Adjust the sensor linkage so that the baseline voltage falls within the acceptable calibration range (e.g., between 740mV and 1000mV to avoid triggering under-limit code 141).

6. 6

   Calibration

   Once the sensor is installed and manually adjusted, run the front suspension calibration process through the tractor's armrest display or service tool to teach the controller the new upper and lower limits.