working my way through the faults on the loon but this one is frustrating me, I've fitted a new n75 boost valve, replaced the vac hoses and tested the dvs and also replaced the brake light switch (for other reasons) but I'm still getting this over boost are there other common causes of this code?, it pulls like a maniac in first but then seems to loose boost like someone ran away with the turbos, or other times if your driving along at 40 and put your foot down it drops a gear and goes like stink but then the boost drops off again, seems to happen once the box changes gear its been a while since i drove another rs6 but I'm pretty sure it pulled hard in every gear. there must be something a miss to generate the code.
i also have a p1660 cooling fan fault and shift lock fault (doesn't engage or light up so you can select gear without pressing the brake which isn't ideal!)
they sure are a money pit does it ever stop
