At what temperature should the radiator fan cease operation?

[RosaStyle]

Operating the vehicle today to assess the temperature sensor. I saw it use the hidden menu diagnostics on the clock. Left the vehicle idle for around one hour and saw the temperature gradually rising. The temperature reached 103 degrees, and the fan activated. Temperature decreased to 71, and the fan remains operational. The vehicle was left idling, and the temperature began to rise again despite the fan operating. Upon reaching 90, I activated the heater at maximum capacity, and the temperature began to decrease. Returned to 68 degrees, and the fan remains operational. No coolant drops are visible, however the level was slightly reduced prior to my testing. The exhaust is unobstructed, with a little accumulation of water from idling. When I accelerate vigorously, I see a little water spray accompanied by white or grey smoke, which subsequently dissipates. Is this a defective temperature sensor or another component that regulates the fan's operation?

[Cincoon]

Activates at 110°C and typically deactivates when the temperature decreases to around 109°C.

[RosaStyle]

Does this indicate that the coolant temperature sensor is malfunctioning, despite the vehicle seeming to register temperatures, or is there a relay that deactivates the fan at lower temperatures? The temperature sensor was replaced in 2021. Do the new models activate the fan at a lower temperature?

[Cincoon]

The ECU monitors the temperatures and activates or deactivates based on the switched earth circuit from the temperature sensor.

[RosaStyle]

If the circuit or sensor is defective, or if there is a problem with the ECU, the fan will not deactivate. I apologise for the multitude of enquiries. I am attempting to comprehend the situation with a restricted knowledge. Every day is an opportunity for learning.

[Cincoon]

If the fan operates continuously, it is likely due to a stored P-code in the ECU, a malfunctioning temperature sensor, or issues with the cabling between the temperature sensor and the ECU, or an internal ECU fault. At 20°C, the temperature sensor on the return wire should register about 2.6 to 2.8 volts; if it shows no voltage, it will indicate -48, if I recall correctly.

[RosaStyle]

To maybe address my inquiry, BMW Repair Guide states:

A malfunctioning MINI R56 coolant temperature sensor may lead to many problems, such as a continuously running electric cooling fan, engine overheating, and/or a check engine light accompanied with sensor failure codes.

[RosaStyle]

Thank you much, Cincoon.

[Lovelyas]

If a basic scanner indicates a coolant temperature of -40°C, it signifies an open circuit, suggesting that either the sensor or the circuit is defective, or an external factor is adversely affecting the signal.

A rapid assessment involves examining the temperatures in a cold state to see whether the reported measurement is believable (i.e., ambient). whether such is the case, disconnect the sensor and check whether it indicates -40°C. It will provide an indicator that the DME is receiving credible data.

[RosaStyle]

My autocom now connects only in EODB mode (another issue to resolve), but I believe I may see the coolant temperature there. I will verify it tomorrow once retrieving the laptop.

[Liveek]

In some vehicles, the low-speed fan remains activated while the air conditioning is engaged.

[RosaStyle]

I had the opportunity to operate the scanner, and with the engine cold, the autocom indicates an engine coolant temperature of 12°C. The air temperature today is around 14 degrees. I removed the sensor, which displayed -40°C, and the fan commenced operation. The issue vanished when reconnecting the sensor. No codes were registered prior to this, although a P0117 Engine Coolant Temperature Sensor 1 Circuit Low was recorded.

[Liveek]

-40°C is the expected reading when the temperature sensor is unplugged. It is likely that with the temperature sensor unplugged, the ECU will enter fail-safe mode and continuously activate the fan.