I know, this is not a s40 but it is a v50 and I read is the wagon version of the s40, so maybe we share the same problems. I am posting this here in hopes of learning something.

I bought a 2007 v50 (non turbo) that I had been looking at. I have had it now for about 6 weeks. I am really liking this car. It is quiet, has a nice ride, get good gas mileage and it has a nice sound system. A few days ago I noticed the temperature reading on the dash of the outside temp dropped 35 degrees. It has been in the upper 90's and low 100s and for the temperature to read at 65 degrees is just wrong. After a day the temperature returned to normal. Today, I drove to the store. I thought the ambient temp in the parking lot will be high and this would be a good opportunity to see if the temperature gauge is working. When I returned to the car I checked the gauge and it read 65 degrees in a parking lot on a upper 90 degree day.

Does the temperature read out not go over 100 and defaults to 65? Is this a symptom of other electrical problems? Has anyone experienced this in other models or cars? I have heard of bizarre error codes appearing with a dead battery. I am wondering if this is an indication of a failing battery. I still have the original battery in the car. How good are the OEM Volvo batteries?
John
91 245 SE, 98 V70, 07 V50