xc90 d5 185 - engine fan on when starting the engine

maartenvd · Aug 16th, 2020, 16:15

Hi everyone,
Bit of an urgent question since I need to travel with my Xc90 on tuesday.
Recently I noticed that the engine fan came on immediately after starting the car with a cold engine. The Fan was running at approx 25% of maximum speed.
The car drives completely normal and temperature gauge in the cockpit is exactly in the middle when the engine is warm.

I scanned the car with VIDA and had the following warning message:
ECM-2000: Engine Coolant Temperature (ECT) Sensor Signal Too High

I checked the live reading of the engine coolant temperature and that value seemed normal: around 70C; engine was warm and was turned off for around 30 minutes when i did the reading.

I am thinking to replace the Engine Coolant Temperature in in the thermostat housing with a new one. I did check the connector but cannot see anything wrong.

Any suggestions? Thanks.

Harley Dave · Aug 16th, 2020, 17:22

Sounds to me like your plan to replace the sensor is a good one if the various connections look otherwise OK.

Certainly a good place to start.

The sensor is usually just a temperature responsive variable resistor (Thermistor) so if, once you get it out and on the bench, you test it with a multi meter it ought to read something other than open or short circuit.

Actually, thinking about it, you could also do this measurement at the connector on the cable to the sensor while it's still in situ. (but disconnected obv...)

You ought to see a change in the resistance from when engine is cold to when engine is hot - as shown by your internal temp gauge, which presumably is controlled by another sensor...

I think the ECT will actually affect more than just the cooling fan - probably fuelling etc too - so worth doing.

Cheers

Dave

Aug 16th, 2020, 16:15	#1
maartenvd Junior Member Last Online: Jan 16th, 2022 05:28 Join Date: Sep 2015 Location: Lausanne	xc90 d5 185 - engine fan on when starting the engine Hi everyone, Bit of an urgent question since I need to travel with my Xc90 on tuesday. Recently I noticed that the engine fan came on immediately after starting the car with a cold engine. The Fan was running at approx 25% of maximum speed. The car drives completely normal and temperature gauge in the cockpit is exactly in the middle when the engine is warm. I scanned the car with VIDA and had the following warning message: ECM-2000: Engine Coolant Temperature (ECT) Sensor Signal Too High I checked the live reading of the engine coolant temperature and that value seemed normal: around 70C; engine was warm and was turned off for around 30 minutes when i did the reading. I am thinking to replace the Engine Coolant Temperature in in the thermostat housing with a new one. I did check the connector but cannot see anything wrong. Any suggestions? Thanks. Last edited by maartenvd; Aug 16th, 2020 at 16:17.

Aug 16th, 2020, 17:22	#2
Harley Dave Volvo Driver Last Online: May 27th, 2024 09:44 Join Date: Mar 2016 Location: Basingstoke	Sounds to me like your plan to replace the sensor is a good one if the various connections look otherwise OK. Certainly a good place to start. The sensor is usually just a temperature responsive variable resistor (Thermistor) so if, once you get it out and on the bench, you test it with a multi meter it ought to read something other than open or short circuit. Actually, thinking about it, you could also do this measurement at the connector on the cable to the sensor while it's still in situ. (but disconnected obv...) You ought to see a change in the resistance from when engine is cold to when engine is hot - as shown by your internal temp gauge, which presumably is controlled by another sensor... I think the ECT will actually affect more than just the cooling fan - probably fuelling etc too - so worth doing. Cheers Dave

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