Follow-Up to Secondary Air Injection System

So wound replacing my SAI pump with a used one (from a fellow RS6 owner here in PDX). Installed it, cleared the CEL/code. All was good for about a week of driving, then the CEL came back on, here are the codes. The pump is definitely coming on for several minutes then turning off (have not timed it) at cold (morning starts or after the car has cooled for some time). Also the CEL just comes on randomly while driving or stopped. Have reset several times only to have it come back on again a day or so later. Any ideas ? Is there some other sensor/item to check ? Thought with replacing with anther what appears to be operational pump the issue would be resolved....

17831 - Secondary Air Injection System; Bank 1
P1423 - 002 - Insufficient Flow
17819 - Secondary Air Injection System; Bank 2
P1411 - 002 - Insufficient Flow
Readiness: 0000 1101

I did some searching on those codes (P1423 and P1411) and they are fairly common. The majority of folks are pointing to broken vacuum lines. Since the pump is running, and you are getting codes for both sides, then I would suspect the common vacuum line that feeds both combi valves.

Look at parts 7. 8 and 9 in this illustration, I believe these are the lines that connect to the combi valves: http://www.realoem.me/Audi/RDW/RS6/2...R/1/133/133040

They would be potential sources of a leak.

Also check out this illustration: http://www.realoem.me/Audi/RDW/RS6/2...R/1/131/131040

parts 23 and 24 correlate to 8 and 9 on the previous illustration.

Gregg

I replaced my EGR solenoid two days ago, (part 4 on the diagram) cleared my code (same as above) but I have not driven it yet. LOL..home on sick leave. Hope to go out tomorrow. Usually that code would come back after a couple trips.

If it is showing a code for each side than it should be some component common to both sides. I have been told the EGR solenoid can fail with intermittent codes like this.

We shall see.

Mike

If you haven't already replaced the rubber hoses with silicone ones now's the time...

Quote:

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Originally Posted by Bigglezworth

If you haven't already replaced the rubber hoses with silicone ones now's the time...

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Did mine about 7 years ago after I found one torn off the drivers side Combi Valve. The silicone holds up very nicely. I checked them all when we had the engine out last year and they still look new! Most of the remaining older stuff is still ok, I had the more difficult-to-get-to lines changed though.

Curious to see the OP's results. Trying to avoid replacing the secondary pump if I really don't need to.

Mike