I have just bought a new style ford Mondeo and have been pleased overall however the outside air temperature display keeps going to -40c and the climate control then goes to hot. The dealer changed the sensor but after about 2 days the temp dropped to -40 again although did recover after about 15 mins. A 2nd visit and the engineer said it was just re calibrating itself and would settle down.

However over the last few days the readings have again become erratic and once it goes to -40, it stays the same irrespective of C of F. Even the salesman hadn't seen this before as it dropped during a visit and I had chance to show him. Eventually the reading comes back to a more normal value.

The garage is unaware of any issues with the sensor so before I go back, is anyone else having a similar problem?

A 2nd visit and the engineer said it was just re calibrating itself and would settle down.

That bit was the kind of b*ll*ckks they make up to make you think that they know what they are doing. Once you know this, you also know that they don't know what they are doing.

I have just bought a new style ford Mondeo and have been pleased overall however the outside air temperature display keeps going to -40c and the climate control then goes to hot. The dealer changed the sensor but after about 2 days the temp dropped to -40 again although did recover after about 15 mins. A 2nd visit and the engineer said it was just re calibrating itself and would settle down.

However over the last few days the readings have again become erratic and once it goes to -40, it stays the same irrespective of C of F. Even the salesman hadn't seen this before as it dropped during a visit and I had chance to show him. Eventually the reading comes back to a more normal value.

The garage is unaware of any issues with the sensor so before I go back, is anyone else having a similar problem?

-40 is the same temperature in F or C, so that doesn't prove much.

In general, I would say that it is likely that it is the temperature reading that you get when it goes open circuit. That could be the sensor itself, the wiring or a connector. As you've already had the sensor itself replaced, it is likely to be one of the others.

Once you've got a -40 temperature, then the heating is likely to go to max.