all of a sudden, at 40k miles the MIL light came on, car feels and drives fine, I checked the fuel filler cap and retightened it, didn't make a difference. brake service light has been on for a month, but I still have some pads left, will change them soon with the rotors, I doubt the MIL came on because of service light. don't want to take it to the dealer, where can I buy the diagnostic tool to read the fault code (depending on how much it is)?

also, does anyone have the DIY for brake pads? I searched around and couldn't find one for Q7..found one for VW Touareg, which is similar...i've done this before on others cars, but want to know if any special instruction with the AUDI. thanx