I used the Carista android app with an old ODB2 bluetooth reader I've had for years, $10 for a week pass to use the coding in the app. You can also use ODB11 or VCDS which are more capable coding tools but cost more and require custom hardware.
I also made some other changes with it: windows down/up with remote key hold, settings menu access while driving, HVAC shows fan speed in auto mode, 4 blinks convenience turn signal blinks instead of 3 (can set 5 as well), auto window up/down doesn't stop with door open. It has settings for mirror dip on reverse but I couldn't get that working right.
It's pretty straight forward to do, well worth the $10 IMHO, even though I'll probably end up dropping the $200 for VCDS eventually cause I'm a nerd.