New Holland ENG 3164 – Engine ECU: Fan Speed Sensor Signal High

This fault code indicates that the signal voltage coming from the fan speed sensor is above the maximum expected threshold. Technically, a "Signal High" condition typically points to an open circuit in the sensor wiring, a short circuit to a power source (battery voltage), or an internally failed sensor.

• T8 Series (e.g., T8.xxx models)
• CR Series (e.g., CR980, CR9070, CR9090 Elevation Tier 4A)
• CX Series

1. 1

   Check the fan speed sensor connections to ensure they are secure, correctly seated, and free of debris.

2. 2

   Inspect the electrical circuit from the main panel (Engine ECU) to the sensor. Look for rubbed, broken, or melted wires that could cause an open circuit or a short to power.

3. 3

   Check the voltage at the sensor connector using a multimeter to verify it is receiving the correct reference voltage and ground from the ECU.

4. 4

   Verify that the fan speed sensor is correctly adjusted and securely mounted (check mounting screws), as improper gap/alignment can cause erratic readings.

5. 5

   Check that the cooling/cleaning fan is physically running at the correct speed and is not mechanically obstructed.

1. 1

   Disconnect the Sensor

   Turn off the machine and disconnect the wiring harness from the fan speed sensor.

2. 2

   Inspect Connectors

   Examine the pins on both the sensor and the harness side for corrosion, bent pins, or moisture. Clean or replace the connector pigtail if damage is found.

3. 3

   Test the Harness

   With the sensor disconnected, use a multimeter to test the signal wire for continuity back to the ECU and ensure it is not shorted to a 12V power source. Repair any damaged sections of the wiring harness.

4. 4

   Replace the Sensor

   If the wiring harness tests good and the connector is clean, the sensor itself has likely failed internally. Remove the mounting hardware, extract the old sensor, and install the new OEM replacement.

5. 5

   Clear Codes

   Reconnect the harness, turn on the machine, and use a diagnostic tool or CAN-bus DTC eraser to clear the inactive ENG 3164 fault code from the Engine ECU.

6. 6

   Test Operation

   Run the machine and verify that the fan speed registers correctly on the monitor and the code does not return.