I know mine (recentish Honda Accord, so you might hope - wrongly -
that it was reasonably accurate) consistently reads 2C high. What's
frustrating is that there seems to be no way of recalibrating the
car's OAT reading. But it's soon to be replaced, probably by a Yeti,
so we'll see how that gets on - hopefully at least the cold temps will
then read more accurately!

JGD