17549
17605
17537
17535
16795
Yea I know they're alot. I'm guessing they're all related. Thanks

 

https://www.audiforums.com/m_300023/tm.htm
u prolly have that link already but just in case. let me do sum hw lol

 

ok the last one has to do with the secondary air injection so it's either a crank breather hose or the pump itself. the others seem like the MAF. try cleaning it but i doubt it'll help. another thing is the air temp sensor but there hasn't been any complaints bout that. it could be both front 02 sensors too but it seems like the code for the 2 banks are related. so im guessing u have a 2.8? auditech79 come here and help lol

 

Thanks for the link.
17549... Load Calculation Cross Check Range/Performance
17605... O2 Sensor Heater Circ.,Bank2-Sensor1 Electrical Malfunction
17537... Long Term Fuel Trim mult.,Bank2 System too Rich
17535... Long Term Fuel Trim mult.,Bank1 System too Rich
16795... Sec.Air Inj.Sys. Incorrect Flow Detected

Techs please chime in on this one...

Ok so one of the precat sensors has an electrical malfunction and both are detecting a rich flow so I'm guessing the other sensor has an electrical fault as well. I know the sec.air pump is working properly because it comes on at every cold start. So either theres a problem with the combination valve or a vacuum leak between the two. But I read that the code is set off by the O2 sensor (IDK if its pre or post) so if the 02 sensor is bad then it'll set off the code when theres really nothing wrong with the sec.air.inj.system. I'm kinda leaning towards this because on occasion the sec.air pump will switch on like at a cold start when I've really been driving looong enough for the cats to be hot.

Either way I'll begin by changing the precat sensors and try to see if there really is a vacuum leak between the pump and combi valve. I'm gonna rule out the MAF, for now, because a faulty precat sensor is confirmed. But I'll keep in mind that a faulty MAF could easily be the reason why the whole system is running rich and fouling the O2 sensors.

Qoute from another forum

 

bump!

I need suggestions/answers. Someones gotta a have little knowledge of whats going on here.

 

Have you tried to look in this link? http://www.bentleypublishers.com/tech/
It's also booked marked in the links section of the VAG Locator site. http://vag-tool.kicks-***.netfor future reference.

 

EVAP valve vacuum pipe split would cause all those problems, the more codes the better which means only one thing is causing the problem

 

ahhh there it is 16795... Sec.Air Inj.Sys. Incorrect Flow Detected, AIR pump,AIR valve, AIR hoses secondary air system

 

Ok so either a vacuum leak there or the combi valve is bad. I still gotta change the precat sensors anyway but can I rule out the MAF? I'm still confused about how the sec.air.inj.system would affect the precat sensors. I thought it only warmed up the cats.

 

Thats correct, having a split vaccum hose between the combi valves won't cause a vaccum leak. There is only vaccum on those lines when the SAP pump is running. You can manually activate the SAP pump with the VAG COM with basic settings block 73 i believe, then listen for the leak.
As for the running rich concern i would definately clean the MAF, the O2 sensor is probably a byproduct of the MAF sensor malfunctioning. So clean the MAF first with some electrical contact cleaner then install the new O2 sensor, not before.
You should be able to audibly hear a vaccum leak if its bad enough to cause a rich fault, especially since its on BOTH banks.