Temperature engine to high error

[bullet123]

I've had a problem for a few weeks on my C5 2.0 163 hp.
I started the car less often, but when I started it, it gave me an Engine temperature to high error and it shows me the maximum temperature level.
The radiator fans were also on.
I stopped the engine, I looked at the expansion vessel, the level was a little below the minimum, I filled it with some spring water, I made a vent and everything was ok.
Yesterday when I started the car again, after almost 2 weeks without starting it, the same problem.
The level now was good in the jar, the liquid was ok, I had another ventilation, and I had no problems.
I left about 300 km, everything is ok, I returned home without problems.
What could it be? I was told there could be a problem with the temperature sensor
Any ideea where is it located?

[wheeler]

The temperature sensors a very common failing parts & will most likely be the cause of this fault.
It will be located in the thermostat housing. Cant remember this model off hand but some sensors come complete with the thermostat & housing.

[Peter.N.]

If it's the same as the 138hp it's a pig to get at. See my thermostat change guide.

Peter