would i have a check engine if my car had a massive boost/vacuum leak? my car is horribly underpowered and when i drive.i have a loud air noise coming from what i think is somewhere near the rear/top of the engine. i cant find any leaks from hoses, if my DV valve is bad would this cause my issue and would there be a.check engine light for a a bad DV?

 

the short answer is yes


the long answer is find all your vac lines and start replacing them


it very well from your description is/could be the egr vac line... runs from the(looking at motor) left rear(shinny spaceship disc thing) to under the intake manifold.... i was following lines on mine and it just crumbled in my hands


but you have about 8 little cloth coated vac lines that turn to dust

 

oh and dv is down under airbox, but you would probably not get a cel for a bad dv

 

thanks for your reply i thought the DV valve was at the back of.the engine, i thought that plastic valve looking thing by the airbox was the part of the pcv return hose.

 

You're probably thinking of the PCV "pancake" valve. The DV is located under that on the charge pipe between the turbo and the intercooler hard pipe that runs across behind your bumper.

EDIT: This is a diagram taken from the FAQ sticky (which you should read)--



#6 is the PCV valve

#19 is the DV

 

i'm talking about the green line

 

I have a 1998 audi a6 and this past week about half of my third brake light LEDs burnt out. Today, the check engine light came on. could the light have come on just from detecting the brake light? regardless im getting it checked later this week just wanted to see what you all think...

 

No, there no way a check engine light could come on due to a burnt LED light.

 

ok thanks. i ran a diagnostic at autozone and code p0411 came up as the problem. Has anyone had any experience with what is most likely the problem? i was just told it involved the air injection system (incorrect flow) AKA faulty air combo. valve. probable causes included faulty air solenoid valve or air pump motor.

 

Sounds like the SAI pump.