Hi,

My 2000 A6 Avant has done pretty well over the years, except I can't seem to get rid of a very intermittent P1423 Sec. Air Flow to Low that started years ago. It probably only happens every 20 cold starts or so on average. It only ever happens on Bank 1.

I have had an independent mechanic and the dealer look at it and over the years they have:

- replaced sec. air pump (probably didn't need to)
- replaced multiple crank case breather/vacuum hoses/pipes
- soaked R/I combi valve to "remove carbon build up"

The last word from the dealer was that if it comes back (which it did) they recommended having the "RH head pulled and cleaned and maybe replaced"

Seems crazy for something that happens once every few weeks! Any thoughts? The big problem with fixing it is that it is so intermittent. Thanks!

 

RH pulled??? P1423 has nothing to do with the head itself. It is only related to the secondary air injection system. Anyways here is a picture of the vacuum system. (There is one located under the hood too)


Considering you are only getting the code on bank 1, I assume that the secondary air pump is fine. I can only suspect that the issue is related bank 1 (passenger side) kombi valve. Here is what I would do.

1. Replace the vacuum line from the kombi valve to the vacuum valves. (Yes I know they did that, but you should do is again for your peace of mind. Also the line will cost you about $2 at a local part store.)
2. Disconnect the kombi valve and check the air inlet hose to see if it is clogged in any ways. You will need a mirror and a flash light to check that. OR just stick a screw driver in there to see if you are getting anything out.
3. Replace the kombi valve.

 

Run Away from that dealer! As hxgasser siad it has to be either the combi valve or vacume line. If those re OK check the connection to the air flow sensor

 

Hello Dear Members,

I have bought an Audi A6 2.7 T 2000 Model a couple of weeks back. I drove it for like 600 miles after I bought it. Last week, I got CEL and the code was P1113 and had the 02 sensor before the cat replaced and after I drove it for about 60 miles and now I am getting P1423.

Please I need your advise and help in figuring out this problem and why these kind of issues are comming with this car. Previously I had 1994 Toyota Camry for 2 years and never a issue with it.

Thanks for your help.

Thammala.

 

Thammala, unless you are familiar with working on cars, I would start by looking for a good independent German auto repair place. Ask your friends, ask BBB, or even try Yelp. With that said, the simple cause maybe vacuum line related. They are pretty cheap to replace. A good mechanic will tell you that.

One thing to remember is that shop rate on German car repair shops are pretty expensive. Even if the parts cost maybe $5 on a couple of feet of vacuum lines, the labor for 1 hour can be much as $125. Yet on the side side of that argument, if the shop knows what they are doing and end up doing the work in 1 hour at $125, it is better than taking it to a shop who does not know what they are doing and finishing the work in 2.5 hours at $75. You see the point.

Good luck.

 

HXGASER - Thanks a lot for your Reply

I went back to my old Camry mechanic who was my friend.

He checked it and first thought that it due to an old cramped hose in pic 1.



Then he changed it with a new hose and cleared the P1423 code.

Today I got the CEL again. Took it to him and he checked some more and it seemed that the pipe in pic 2 was loose, So he put some straps and fixed it for now.

I dont know what that pipe is, Can you please let me know so that I will order it and get it fixed properly.





Once again, I am thankful to you and to this forum.

 

That looks like a breather hose. Next time please take pics with anything else but a cel phone.

 

Sorry, I had only my cell phone when i went to the mechanic.
Now I am noticing that the mileage has come down drastically. I was getting around 20-22 mpg but now it came down to abt 15-17 mpg.
I am not sure why. Using Shell premium fuel since I bought it.

 

Which one is the "combi valve"? I have this same problem on my wifes 2000 A5 Avant. Constant DTC 1423

I replaced all the vacuum hoses on the top of the engine and the passenger side "vacuum value" because I broke a nozzle trying to get the dry rotted hoses off, and that stopped the DTC 1423 for about 7 months, then it came back again, the one long one on the passenger side still needs changing.

Can you point out in the diagram which one is the "combi valve" is that the same thing as the ERG valve?

Her tag is due next month and I need to fix this so I can get emissions to pass so I can get a tag.

 

The older models (C4s) had the EGR valve- don't know exactly if up to last year model (1998), while the newer models have the 'combi' valves... same function