Case IH 2186 – ENG (Engine Controller / Engine ECU): Supply Voltage to the accelerator pedal position sensor too low

This condition occurs when the control unit measures a voltage below the acceptable operational threshold (typically below 0.3 volts) at the signal input of the accelerator pedal potentiometer. This usually indicates an open circuit, a short to ground in the sensor's wiring harness, or an internal failure of the sensor itself.

• MX Magnum
• Case IH MX Magnum Series
• Case IH TG Series
• Case IH Steiger Series
• Case IH Puma Series (115, 125, 140, 155, 165, 180, 195, 210)
• Case IH Maxxum Series (100, 110, 115, 125, 130, 140)
• Case IH MXM (120, 130, 140, 155, 175, 190) and MXU Series

1. 1

   Inspect the accelerator pedal position sensor and its electrical connector for dirt, moisture, corrosion, or backed-out pins.

2. 2

   Turn the ignition key to the ON position (engine off). Disconnect the sensor and use a multimeter to verify that the Engine ECU is sending the correct reference voltage (typically 5V) to the sensor.

3. 3

   Test the signal, ground, and supply wires between the accelerator pedal connector and the Engine ECU. Look for infinite resistance (open circuit) or continuity to ground (short to ground).

4. 4

   Ensure the tractor's overall system voltage is healthy, as low battery voltage can sometimes trigger false sensor supply faults.

1. 1

   Disconnect Power

   Disconnect the negative battery cable to prevent electrical spikes during the repair.

2. 2

   Harness Repair (If Applicable)

   If the diagnostic checks revealed a short to ground or a broken wire in the harness between the pedal and the ECU, repair the damaged wiring or replace the affected harness section.

3. 3

   Sensor Replacement

   If the wiring and ECU supply voltage are intact, the accelerator pedal position sensor has failed internally. Unbolt the faulty sensor/pedal assembly from the cab floor and disconnect the harness. Install the new sensor and secure the mounting hardware.

4. 4

   Restore Power

   Reconnect the sensor harness and the negative battery cable.

5. 5

   Clear Codes

   Connect an electronic service tool (EST) to the tractor's diagnostic port and clear the inactive 2186 fault code.

6. 6

   Pedal Calibration

   Depending on the specific tractor model (e.g., MXM series), you must perform an accelerator pedal calibration using the tractor's H-Menu or service tool. This process registers the new sensor's voltage at the 0% (fully released) and 100% (fully depressed) positions so the ECU can accurately map throttle input.