After more research I found my CEL codes on a 97 a4 2.8 12v 5 speed.

P0401 EGR system Flow too low (could this be causing the P1402?)
P1402 EGR Valve Circ Short to B+ (Am I looking at a clogged or dead EGR)

P1504 Intake Air Sys.Bypass Leak Detected (Is this a vacuum leak or a ICV problem?)


I'd appreciate any help on getting these resolved. Thanks!

 

P1402 is likely causing P0401 and you likely will need the EGR valve to be replaced. There are, however, various things you can try on the EGR valve from cleaning it out with carb cleaner to pulling it apart and more thoroughly doing so (see http://www.g20.net/forum/showthread.php?t=81217 though it's for a different car)

I would think that you have a vacuum leak for the P1504. I think it means that unmetered air is getting in. How is the car running?

 

The car doesn't have a fast idle on cold start. It starts- almost dies and then settles into an idle around 900 rpms never going above this. Otherwise it drives fine-but has those CEL codes.

The idle issue leads me to believe the EGR and ICV are all gooped up and need cleaned. The 1402 code worries me because if it s a short on power the valve is dead. Only 106K on it but I heard the EGV valves rarely fail but just get clogged.

Next question is a vacuum leak could be causing the idle issue also. Where do I look?

 

You look all over the place, unfortunately, because these cars have tons of vacuum lines. Clean out the EGR valve thoroughly and see where you're at for that. Clear your codes every time you think you might have solved a problem. It might take a while for a code to come back and thus for you to know.

 

Thanks Dragon I appreciate it...