wookie624

Hey all,

First time here but i looked around and im still at a loss..

2007 audi a4 2.0t with 81k miles


we bought it and it had a pending p0299 code and it went away then it came up with a evap large leak with the p0299 code.

i replaced the gas cap and so far the evap code hasnt come back but im still waiting on the evap system to set.

i replaced the diverter valve with a new one this morning and drove all day no problems, went to get on the freeway and as soon as i stepped on it then check engine light came on (p0299)

i also replaced the plugs, the air filter and oil and filter.

i use my bluetooth obd2 with torque and it shows my boost is going to 20-30 psi and then dropping right away to about 12 psi and it creeps down to 8psi steady.

even with the check engine light on, i get sport and power shift modes, 12 psi then down to 8psi solid on WOT hill climbing.

its running about 1/4 to maybe almost 1/2 temp, running premium gas in it.

i looked at the PCV valve and its new and the diaphram is good, i ordered a new one just to be sure.

what else could cause this? my wastegate arm is not wiggly or anything. the vaccums going to the n75 are fine, all my intake hoses and intercooling piping are tight.

only things i noticed is a small amount of oil in the intake hoses from the intercooler to the intake manifold.

Should i be calling the dealer i got it from? is it a easy fix? do i just drive with the check engine light on?


also, when i take off the oil cap it doesnt suck it back on or anything but it does change the idle to a rougher idle.

THANKS! please please please help me.

wookie624

so i solved it myself.

i replaced the n75 valve with new vacuum lines and clamps and now its boosting fine, no check engine lights, more power and preformance. just posting this out here since it seems this forum rarely gets any replys.

maverick17036

I'm having the exact same issues as you. I have a 08 A4 Cabriolet with 78k miles. P0299 and P0456 (evap leak) codes. Still getting boost. Replaced DV with new piston style, didn't fix the issue. Got oil leaking around same area. WG rod not wiggling, nice and snug. Everything else I read is saying bad turbo because everyone has that WG play. Your post is giving me some hope! Thanks Wookie!

maverick17036

And as a followup, the N75 ended up being my issue! I was boosting at max, 10-12psi before the fix. Now my max is at least 15psi and the CEL hasn't come back with a new N75 installed. Again thanks for your follow-up!