Case IH P2 – Engine Control Unit (ECU): Foot Throttle Position Sensor, Open Circuit Or Current Below Normal Range

The control module is detecting an open circuit or a current draw that falls below the normal operating parameters from the foot throttle position sensor (potentiometer). This means the sensor is either unplugged, the wiring is broken (open circuit), or the sensor's internal potentiometer has failed and is no longer returning a valid voltage/current signal to the controller.

• MXM
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190
• Farmall 50A
• Farmall 70A
• Farmall 95U Pro EP
• Farmall 105U Pro EP
• Farmall 115U Pro EP
• Puma
• Magnum
• Axial-Flow 5088
• Axial-Flow 6088
• Axial-Flow 7088
• Axial-Flow 5130
• Axial-Flow 7130

1. 1

   Inspect the foot throttle position sensor connector (e.g., Connector X-321 on Farmall models) for loose pins, corrosion, or moisture.

2. 2

   Check the wiring harness leading from the foot pedal to the ECU/VCM for any visible breaks, chafing, or an open circuit.

3. 3

   Check the associated fuses that supply power to the universal controllers and sensor circuits (such as F-021 or F-051, depending on your specific model's electrical schematic).

4. 4

   Use a multimeter to test the sensor's potentiometer resistance. If it reads completely open (infinite resistance) across the signal pins, the sensor is internally faulty.

1. 1

   Turn off the machine, remove the key, and disconnect the battery to prevent electrical spikes.

2. 2

   Locate the foot throttle position sensor, which is mounted directly to the linkage at the base of the foot throttle pedal.

3. 3

   Unplug the electrical connector (e.g., X-321) from the sensor.

4. 4

   Remove the mounting hardware securing the rotary position sensor to the pedal assembly and remove the faulty sensor.

5. 5

   Install the new foot throttle position sensor and secure the mounting hardware.

6. 6

   Reconnect the electrical harness connector.

7. 7

   Reconnect the battery.

8. 8

   Turn the key switch to the "ON" position.

   Note: On many Case IH models (like the MXM series), replacing a potentiometer requires a calibration procedure via the H-Menu or Electronic Service Tool so the ECU can learn the new sensor's minimum and maximum voltage values.