New Holland ENG 2186 – Engine Controller (Engine ECU): Supply Voltage to the accelerator pedal position sensor too low.

The reference voltage (typically 5V) supplied by the control module to the accelerator pedal position sensor (or hand throttle potentiometer) has dropped below the acceptable operating threshold. This is usually caused by a short to ground in the wiring, a damaged harness, an internally shorted sensor, or a failing control module.

• T-Series (TM, TS, TN, T6, T7)
• 8000 Series (8670, 8770, 8870, 8970)
• CR and CX Series (CR920, CR9090, CX840)
• Magnum
• Steiger
• MXM
• MXU
• Wheel loaders
• Excavators

1. 1

   Visual Inspection: Inspect the accelerator pedal assembly, hand throttle, and the wiring harness leading to the Engine ECU. Look for chafed wires, pinched harnesses, or micro-cracks in the circuit traces.

2. 2

   Connector Check: Disconnect the sensor and inspect the pins for corrosion, moisture, or loose connections, which are common causes of voltage drops.

3. 3

   Voltage Test (Unplugged): With the key ON and the sensor unplugged, measure the supply voltage at the harness connector. If the voltage is still too low, the issue is a short to ground in the wiring harness or a faulty Engine ECU.

4. 4

   Voltage Test (Plugged In): If the supply voltage is correct when unplugged but drops significantly when the sensor is plugged back in, the sensor itself has an internal short and must be replaced.

5. 5

   Fuse Check: Check the fuse box for any blown fuses related to the sensor power supply or ECU.

1. 1

   Disconnect Power

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

2. 2

   Access the Sensor

   Locate the faulty accelerator pedal position sensor (APS) or hand throttle potentiometer in the cab.

3. 3

   Repair Wiring

   If diagnostics revealed a short to ground in the harness, trace the wire back to the Engine ECU, repair the damaged section, and secure it with heat-shrink tubing and loom.

4. 4

   Replace the Sensor

   If the sensor is internally shorted, unbolt the sensor (or the entire pedal assembly, depending on the model's design) and disconnect it from the harness. Mount the new OEM replacement sensor and plug it in.

5. 5

   Restore Power

   Reconnect the battery.

6. 6

   Calibration/Relearn

   Turn the key to the ON position. You may need to perform a throttle relearn procedure (using a diagnostic tool or specific key-cycle sequence) to tell the ECU what "closed throttle" and "full throttle" voltages look like.

7. 7

   Clear Codes & Test

   Clear the ENG 2186 fault code from the Engine ECU using a diagnostic scanner. Start the engine and test the throttle response to ensure the code does not return and the machine does not enter limp mode.