2008 audi 2.0t gas cap info
 

ok so my car engine light is on and it said I have an evaporative emission system leak (small). I was searching about this and it said a gas cap is a common problem, when usually when I take gas caps off other cars it makes noise( like pressure is being released) my audi tt gas cap doesn't make a noise or click. are audi tt gas cap suppose to click?