Ambient temperature dash reading incorrect.

[Stevex]

Hi, I've had a 2.0 TDI Bluemotion DSG estate for about a month now. Yesterday I noticed the dash ambient temp readout was 16 degrees, although real outside air temp was only 8 degrees.
Today it was initially reading about 14 degrees but went up to 16.5 degrees, even though oat was still approx 8 degrees.
I removed the temp sensor and tested its resistance over the 2 plug terminals and it appears ok, reading about 1.7K Ohms in a cold garage. When I hold the sensor in my hand the reading goes down as expected.
I've found a genuine replacement on the web for approx £20, but with what appears to be a good sensor, I'm wondering if there is anything else that can affect the dash reading.
Anyone got any ideas or had the same problem?

[Mittens247]

Common fault and the common solution is just to buy a new one and replace it. Mine was reading 4-5C low and the new one now shows the correct temperature. Never had this issue on any of 10 or so cars I have owned previously.

[Stevex]

Yes, I've ordered one, prices are all over the place but found a new oem for £20.
I took the old one off, plug internals looked as new; since refitting it seems to have had a word with itself though and is back to normal.
I'll fit the replacement and keep the old one as a spare.

[MDickson]

I have the same issue apart from mine is reading - 4 degrees if not lower.
Does anyone have the part number handy at all? Thanks.

[Mittens247]

3G0820535B is the part no. I fitted.