Hi, have a 2005 A3 1.9tdi sportline, done a handsome 150k, last week did a small service, replaced oil and all the filters, when I started the car up had the flashing engine management light on. The twirly one.

Had a friend connect his reader and came up with a code P0571 also 16955 with an implausable signal & brake switch, must add at this time that all 3 brake lights come on when the ignition is on.
Strangely the brake lights work fine when the key is out. So weird.

After some forums and advice changed the brake light switch and also replaced all the bulbs in the rear clusters.

Now I still have the damn flashing engine management light on the dash. Do I have to clear the code or would the fault reset itself? And what else can I check?

I have tried unplugging the brake light switch, brake lights still on and engine light flashing
I have tried unplugging the rear tail lights one at a time, same result, other brake lights still on and engine light still flashing, help please anyone...