Jer

Looking at an Allroad w/a CEL that is on and this owner said this was the result of the dealer scan for codes:

17831 Secondary air injection system bank 1 insufficient flow P1423
17819 Secondary Air injection system bank 2 insufficient flow P1411

Can someone help me with this? Is this the actual code because I'm not turning up with anything in any searches. I would like to know the possible causes for the CEL as well as what it might take to repair. Thanks for the help!

LuvnhatemyA6

Faulty ie dead secondary injection air pump?

Jer

Could it be the diverter valve(s) or related vacuum lines?

Rocky-in-Connecticut

I bet your vacuum lines are old and cracked. Replace vacuum lines, especially to the combi valves

Jer

Combi-valves=diverter valves?

If that's so is it also possible that one of both have failed? I now see that the vacuum lines seem to be a common culprit but since this car is two states away I'm trying to figure out an absolute worst case scenario prior to pursuing this vehicle further. Thanks!

A6 4.2 litre

<ul><li><a href="https://forums.audiworld.com/a6/msgs/669628.phtml">link</a></li></ul>

Jer

Thanks so much for the link. This is why I normally try to refrain from posting as usually it's been answered already. A search for all four codes (both have two codes and I tried all four) turned up nothing so I think maybe the search was having some issues when I looked.

Now I wonder if it's the vacuum lines greater than 90% of the time or if there's a good chance it could be something more and what the cost of those parts might be.

Rocky-in-Connecticut

combi valves are emissions related. They regulate the amount of secondary air flow.

Diverter valves are boost related. They regulate the amount of turbo recirculation.

plova

Hi Jeremy,

Hope this helps. I have had the same fault codes after I ran a VAG-COM on by 2001 A6 Avant.

The Bentley Manual has an Audi Technical Bulletin which addresses this problem. For reference the bulletin number is 01-03-08.

This is what is written on the bulletin:

Condition
Malfunction Indicator light (MIL) ON. Diagnostic Trouble Codes (DTC) P0300, P0411, P1128, P1411, P1423 stored in DTC memory.

May be caused by a cracked or broken (braided cloth covered) vacuum hose to the Secondary Air Injection Combi-Valve.

Most common DTC's associated with broken or cracked vacuum hoses are P0300, P0411, P1128, P1411, P1423.

The Bulletin suggests for service to inspect all lines associated with the Secondary Air Combi Valves to check for cracks or breaks.

As I mentioned before I had the same codes as you mentioned, plus a few other ones. I took the plastic engine covers off and inspected the hoses and sure enough they seem to be cracked. It is a bit hard to determine by just looking, as the cloth braiding might hide an obvious crack, but in my case the cloth was very brittle, so I am sure this is what is causing my problems.

It might be something as simple as replacing the hoses - about $30 - $35 in parts if you do all. From my experience and others on this board it appears that the hoses are prone to breakdown from the engine heat over 4-5 years.

Jer

I'll do some research on those bad boys.