Hey folks. Granted it's not a golf but i've had my 2006 A4 2.0tfsi quattro special edition (longest car title ever!) for a little over a year but recently, ok not recently, over 6 weeks ago but i'm a postie and been pretty busy, time of year and all... anyway the car started going into limp home mode whenever it boosts. If i drive it VERY carefully so as to keep it off boost she runs fine, but if i deliberately make it boost (or even accidentally) it goes into limp home mode and can't even get out of it's own way! It's not an intermittant problem as it happens every time the car boosts other than if i have to launch it out of a roundabout in 1st, it takes off like a train, but once into 2nd and boosts it drops into limp mode. Any gear, any speed, if you give it enough throttle to boost it'll drop to limp mode and remain there until you turn the key off then on again. The most annoyingthing is that it has never, ever given a fault code or a CEL and i really cannot afford to replace bits and find out there was nothing wrong with the old one so i would really appreciate any and all help in arriving at a likely diagnosis. I've tried a bluethooth obd adapter and Torque, an older version of vag-com, vcds and a friends cheap handheld code reader, none presented and codes, not even one off intermittent codes. Thanks in advance. Bundy.
Sounds like some data logs from vcds are needed. If you can do the logs from the APR site some diagnosis maybe possible - but the lack of any fault codes is a worry that it may have been remapped... http://www.goapr.co.uk/support/datalogging.php
Sounds like it was been remapped and the actual boost is exceeding specified and triggering a diagnostic limit threshold. Or boost control to waste-gate is being bled to atmos, also exceeding diagnostic limit threshold.
Odd that it's going into limp home and not throwing a code, because it's easy and cheap I would check the fuel pump follower hasn't worn through although I would expect it to throw a code.
i dont think the car has been remapped, although i dont know for sure. Having driven both a remapped and a stock tfsi, it drives just like a stock one, not enough torque low down to have been remapped imo. i'll have to try and get vcds up and running again, my laptop corrupt its drive so had to reinstall and upgraded to winblows 10 at the same time. Hmm, this sounds possible since it was fine then went into limp on full throttle, and now goes into limp every time it boosts, even on part throttle. i wonder if a hose has popped off the n75 or something. think this is possible? i was under the impression this issue was solved for the BUL engine, so i read anyway.
The fuel pump follower is an issue on all engines I believe... As you don't think it has been remapped - going over the vaccum system to the n75 seems to be a sensible idea. If no luck there also check the PCV and blow off valve for leaks.
if the weathers better than baltic tomorrow i'll go over the n75 lines. Perhaps wrongly, i'd ruled out the blow off valve because the car had a new turbo at 98k miles, 3k before i bought it (108k now) so i kinda assumed it would be the new type. The corrugated pipe from the pcv broke while i was test driving the car, although we did not know what the issue was at the time, just that it had thrown a CEL and gone to limp, the last owner got it checked out and replaced by his audi dealer. Again i assumed, perhaps wrongly, that they would of checked the pcv valve. Something else to add to the check list. Thanks.
