New Holland ENG 3165 – Engine ECU (EDC - Electronic Diesel Control module): Fan Speed Sensor - Signal Low

The Engine Control Module has detected that the voltage signal returning from the fan speed sensor has dropped below the minimum acceptable threshold. This condition typically indicates a short to ground in the sensor's wiring circuit, a severely corroded connector, or an internal failure of the sensor itself.

• CR9090
• CX8080 Elevation
• CX8090 Elevation
• T8.xxx Series
• Magnum 235–340 (Series 4)

1. 1

   Inspect the wiring harness leading to the fan speed sensor for chafing, melting, or pinched wires that could cause a short to ground.

2. 2

   Disconnect the fan speed sensor and inspect the pins for corrosion, moisture, or pushed-out terminals.

3. 3

   With the sensor disconnected and the key in the ON position, check the sensor harness connector for the ECM pull-up/reference voltage (typically 5V). If voltage is present, the wiring to the ECM is likely intact, pointing to a failed sensor. If absent, there is an open circuit or wiring issue.

4. 4

   Check the signal wire for continuity to ground to verify if a short-circuit exists in the harness.

1. 1

   Cool down machine

   Turn off the machine, remove the key from the ignition, and allow the engine and cooling system to cool completely.

2. 2

   Locate sensor

   Locate the fan speed sensor on the engine cooling fan drive assembly (or cleaning fan drive on combines, depending on the specific application logging the engine code).

3. 3

   Disconnect harness

   Depress the locking tab and disconnect the electrical harness from the sensor.

4. 4

   Clean area

   Clean the area around the sensor to prevent dirt or debris from entering the mounting port.

5. 5

   Remove retaining bolt

   Remove the retaining bolt(s) securing the sensor to the housing.

6. 6

   Remove old sensor

   Carefully pull the old sensor out of its mounting bore.

7. 7

   Lubricate O-ring

   Lubricate the O-ring on the new sensor (if applicable) with a small amount of clean oil to prevent tearing.

8. 8

   Install new sensor

   Insert the new sensor into the housing and install the retaining bolt, tightening it to the manufacturer's specified torque.

9. 9

   Reconnect harness

   Reconnect the electrical harness, ensuring the connector clicks securely into place.

10. 10

    Verify repair

    Turn the key on, clear the inactive fault codes using a diagnostic scan tool, and run the engine to verify the fan speed registers correctly and the code does not return.