Don't pay for the reading of codes invest it in your own code reader. I've seen some really cheap ones but having never owned a car with electric windows let alone one with a OBD2 socket I've never tried one.
I did stumble on this kind of thing a few months back and it got me thinking
Best OBD car apps for Android: turn your phone into a black box
It is a cheap thing that connects via bloooo tooooof to an android smart phone - might be worth a gamble. (If you can afford it)