# Fault codes: P0491 and P0492



## glass (Feb 15, 2007)

Hello All,
I was told that these are affiliated to a problem with the air pump (not the one you pump the tire up with) -- Can someone help me locate the air pump?
Hoping to find a loose hose or something I can fix.


----------



## glass (Feb 15, 2007)

*Re: Fault codes: P0491 and P0492 (glass)*

VW tells me that the EGR Valve is bad...


----------



## glass (Feb 15, 2007)

*Re: Fault codes: P0491 and P0492 (glass)*

But guess what, I just learned that EGR valves were only used in TDI's.
Did someone switch engines on me?
Or is this VW shop a con shop?
My money is on the latter.
Updates tomorrow...


----------



## depiry (Feb 16, 2005)

Check Club TouaregIY and technical,Component locations,Marty


----------



## depiry (Feb 16, 2005)

P0491,P0492 Relate to secondary air system solenoids and air flow,can you give me the 3 letter code for your engine and I will post the codes,Marty


----------



## glass (Feb 15, 2007)

*Re: (depiry)*

Hey Marty, thanks for pointing me to CT, I was able to locate that AIR pump. I googled the two codes, and found folks who had this problem and this pump was the culprit, but they had bmw's and porche's.
My engine code is -- BAA.










_Modified by glass at 4:21 PM 5-27-2008_


----------



## depiry (Feb 16, 2005)

PO4910491 16875 Secondary Air Injection System Insufficient Flow Bank 1 

Secondary Air Injection (AIR) system
Secondary Air Injection (AIR) system, checking for proper seal


----------



## depiry (Feb 16, 2005)

PO4920492 16876 Secondary Air Injection System Insufficient Flow Bank 2 

Secondary Air Injection (AIR) Solenoid Valve
Secondary Air Injection (AIR) valve, checking
Note


----------



## glass (Feb 15, 2007)

*Re: (depiry)*

I kindly thank you again Marty.
Now, I'm still guessing here, but I assume the solenoid and valve are part of the AIR pump? I'm going to do some research.


----------



## depiry (Feb 16, 2005)

A friend had a 2004 V6 that had similar codes,reset all faults with a Vag-Com and all was ok ,never returned,Marty


----------



## glass (Feb 15, 2007)

*Re: (depiry)*

After I was mis-diagnosed, I went to the auto zone and had them reset my light. Its been 2 days since then, still no engine light; hopefully this will not reappear on mine either.
Might have to go ahead and purchase a VAG.com cable -- I thought it was just to change settings. Read a post where someone said they used the program to test components, that's pretty cool.


----------



## glass (Feb 15, 2007)

*Re: (glass)*

Final diagnosis follows -- The error codes were a result of a bad combi-valve (which is similiar to an egr valve).
Had to install parts 022-131-101-B (valve) & 078-131-120-K (gasket).
Funny but good thing is, the combi valve was covered under my extended warranty, but an EGR was explicitly mentioned as not covered. Glad they dont know that they are similiar parts.
Just hit 70K.


----------



## german performance (Sep 5, 2004)

combination valves could either have a vac leak. Or can be carbon clogged, or jammed from carbon build up. fairly common fault


----------

