hi

How can you check that the Engine coolant temperature sensor is working?

thanks

Try and run the engine warm, with the sensor connected, and then take the sensor off, and see if the engine changes sound and rpm, and if the fan starts.

Best Regards

Morten

you could measur the resistance of the sensor with a multimeter

Yes, he could do that, but the resistante changes accordig to temperature.

S

when the engine is cold the resistance will be about 4KƱ

at normal running teperature is will be around 300Ʊ

remember that the sensor has 4 terminals, there are two totally inpependant sensors in the same unit....

pins 1 + 3 are for the engine management system

pins 2 + 4 are for the temperature gauge in the instrument cluster

I have reset the ECU by disconnecting the battery for about 20 minutes. Then I gave it a good run on the motorway. Hopefully, this has reset the computer and it will use less petrol.

The dial on the dash board that measures the coolant temperature sits nicely in the middle of the scale after the engine has warmed up. The fact that this sensor is working, would it be reasonable to assume that the coolant sensor which feeds the ecu is also working properly or are the 2 sensors completely different?

The dial on the dash board that measures the coolant temperature sits nicely in the middle of the scale after the engine has warmed up. The fact that this sensor is working, would it be reasonable to assume that the coolant sensor which feeds the ecu is also working properly or are the 2 sensors completely different?

See the reply above.

See the reply above.

:iagree:

A dealer diagnosed a faulty temperature sensor on my Felicia using their diagnostic kit (1551/2): the coolant temperature reading was way too high, even for a hot engine. I also later diagnosed a similar problem using VAG-COM. Although the engine was cold the coolant temperature logged was around 80 degrees C.

the sensor in the rad on my 1.6 has only got two pins???????????????

the sensor in the rad on my 1.6 has only got two pins???????????????

that's the switch for the radiator fan..

it will be open circuit when the coolant is below a set level, and closed to earth when the coolant is hot..... to test it's operation, unplug the wiring plug from the switch and bridge the two wires using a hair pin, if the ignition is on then the cooling fan should start up:D

had to do that the other day. got a switch in the car wired to it at the mow.

and the fan should work when the keys are out, shouldnt it???????

and the fan should work when the keys are out, shouldnt it???????

it will work after the engine has been run.... but after a set period of time the relay that powers it is cut off:O

mine has a switch wired in, in the place of the one in the rad. and when you flick the switch the fan will come on, evan if the car has been off all day.

do you think the relay might be slacking???

err.. no..

it depends on what year it is.... they changed them on 1996 iirc

1998

Just tried the multimeter test on two separate coolant temp sensors (with the meter set at X1kƱ)

The first one was 5kƱ and the second one was 4.5kƱ

After letting them sit for two minutes in just boiled water, the first one read 1.8kƱ and the second was 2kƱ.

Is this correct?