2005 V70 2.4 - External air temperature reads 8-10F higher

PentaxGuy · Post by **PentaxGuy** » 23 Feb 2009, 10:33

I think there may be a problem with the external air (ambient) temperature sensor in my 2005 V70 - for the past couple of weeks, the reading on my dashboard is about 8-10 degrees higher than the actual air temperature even after driving outside in cold weather. For example, the reading on my dash was 37F, while the actual temp was 28F as indicated by multiple other sources (radio, weather channel, thermometers). Does this indicate a need for cleaning the sensor, or some air intake (if so, where is it)? As this is something new, it probably does not indicate proximity to the engine etc. Is this anything to worry about?

Post by **billofdurham** » 23 Feb 2009, 11:56

The sensor is in the door mirror so shouldn't be affected by engine temperature anyway.

I don't think it is anything to worry about as it doesn't affect the car's performance and I would just ignore it.

Bill.

Post by **MadeInJapan** » 23 Feb 2009, 14:21

I agree with Bill- if it really bothers you, for some $$, the dealer can probably recalibrate it with their software.

Post by **VCA** » 24 Feb 2009, 06:21

MadeInJapan wrote:I agree with Bill- if it really bothers you, for some $$, the dealer can probably recalibrate it with their software.

It can't be re-calibrated. However, if you're of a DIY bent, check out connector A into the PDM* (LHD) or DDM* (RHD) (the outside temp sensor is always on the RH mirror, regardless on the handedness of the car), and specifically the resistance between A14 (top right of the connector with the clip facing up and you looking at the pins) and A18 (4th from the left, bottom row). The resistance is 2450-ohm at 20C and 1550-ohm at 30C.

*The PDM and/or DDM is the door window switch pack on the respective door. Yes, the window switches have computers in them

PentaxGuy · Post by **PentaxGuy** » 24 Feb 2009, 10:40

Thanks guys! I am not bothered by it, as long as it does not indicate an underlying problem with the engine etc. Cars have become so complicated these days there are computers everywhere - my first car had a handle I cranked to roll up the window, and this Volvo has a computer in the window switch!

Post by **billofdurham** » 24 Feb 2009, 12:29

Cars have become so complicated these days there are computers everywhere

I totally agree. My first car did not even have an engine temp gauge, never mind an outside temp gauge. Speedo and fuel gauge were the only instruments. The second one did not have a fuel gauge, just a warning light that came on at 1 gallon left. That was ably assisted by being able to look into the tank and see how much was in there.

Of course that was so long ago we had a man with a red flag walking in front.

Bill.