How do you get onboard diagnostic "check" button to work?
 

I heard that the check button below the HUD can be activated at or below 5mph and it tells you fluid levels for coolant,brakes,etc. How exactly is this system activated and how do you know its working? Also, how do you know when you need coolant? Thanks.

02 A4 3.0 quatt:confused:

Re: How do you get onboard diagnostic "check" button to work?
 

When you hit the check button, the display in the instrument cluster cycles through a bunch of warning. Not that you need to hit the button to tell if something's wrong: the warning should pop up on its own and stay on the display if there's a fault that you can tell from the display anyway.

Best way to see if you coolant? Check the reservoir :)

Re: How do you get onboard diagnostic "check" button to work?
 

You hit the button and it goes through the checks. Not like you need to do this though as every time you start it up it does it automatically anyways. If it senses through its mind tricks you need something it will sound a warning that can't be missed, even for gas.

As said, to see if you need coolant check the reservoir.