ABS light now off, but ESP turns on randomly
 

I have a 2004 2.7T A6 with 60K miles.

ABS / ESP lights went on, and it ended up being the break light switch.

I replaced the switch, and the ABS system is now working without issue.

However, now the ESP light comes on after 2-10 miles of driving. Whenever I turn the car off, the ESP system resets to okay but then trips out again.

Not sure what is wrong, looking for some ideas.