Volvo s70 t5 engine coolant temperature

[Povar]

Hello, last week I bought Volvo s70 t5 2000.
I have engine coolant light on,
I read in the forums that is the ECT sensor.
The obd read engine coolant -41c
I tested the sensor and the result is about 400 ohm after 3 minute driving.
It means that the sensor is OK!
What I need to check? I read somewhere to check the wiring.
Thank you!!!!

[Ozark Lee]

The engine coolant light is a coolant level warning and it is based on float switch in the coolant overflow reservoir. If the coolant level really is low just fill the overflow tank to the mark and it should go out. If the level is indeed OK check that the sensor is plugged in. You need to remove the tank from the mount to check it.

If the level is OK and the sensor is plugged in it may be a bad level sensor. Occasionally the float will stick but a good smack on the tank will usually pop it free.

An ECT sensor error only shows up with the lambda light and a scan. It can be bad and not show up on a scan but you have already made the resistance measurements.

...Lee

[misha]

...The obd read engine coolant -41c...

I hope that you mistyped that minus 41c(-41c).
About red coolant light....lee allready answered that.

[abscate]

Preevyet, Povar

You can find the resistance map for the ECT on this forum, perhaps searching the '1999 ECT resistance' phrase as several members with that year have posted up

[s10lowrider1994]

It's probably the sensor underneath your reservoir if the reservoir is full. There's a float inside that can stick too but in my experience it's usually the sensor that's failed.