Hi all, I just recently bought my i20 N, its got 51k miles on. Every time I put the car into N mode, the warning in the title appears. From what I have researched it seems to be a faulty sensor? From the cars last service I can see the brake pads were measured at 9mm. How low should they be before the warning starts appearing, and what are my options to stop it from happening? Thanks all.
Not my picture, just an example from Google Images:

Not my picture, just an example from Google Images:
