I have a 2001 A6 Avant with a check engine light and codes that indicate the the secondary air flow is too low on both banks. I checked the air pump and it blows strong like a hair blower. I checked for leaks to the port on the front of the engine from the air pump and found none. I checked the relay next to the ECU and that was ok. Checked the 2 vacuum pods that open to let air into the heads, that was ok. Check the solenoid that allows vacuum to open the diaphragms, again ok. All vacuum lines are new. I now have my cheapo scanner velcro'd to the dash board so I can erase the codes. They come back on after 25-40 miles. Could it be something in the ECU? It is closed finite system and all components check ok. Any/all advise would be greatly appreciated. Thanks!

I would check first thing in the morning , make sure pump comes on with a cold engine , check for vacuum at the air valves at the back of the cylinder heads , should be 15-20" of vacuum. If the valves both operate , you have good pressure blowing into them from the pump it is a possibility that you have clogged secondary air ports in the cylinder head.
How long have the codes been there? , Did they both show up at the same time?

Air pump only runs during cold start up to get the cat's hot quicker, like M5S5 mentioned. I have seen a number of these where everything appears to be fine except the combi-valves (rear of heads) don't open all the way, or at all. Only fix is to replace them. A quick check, relatively speaking, is to remove the tubes at the valves (carefully, they're most likely brittle). Hook up a vacuum pump to the vac. supply hose and apply a vacuum. The exhaust noise from them should be fairly loud. If there's none or only a slight increase in noise then the valves are faulty.

I forgot to mention that I also had an Audi guy clean out the ports in the head. He modified a flexible spring loaded "grabber" to fit in the end of a drill and "reamed" both ports. Then applied compressed air and heard it through the exhaust. Both codes come on at the same time. All the vacuum lines have been replaced with new rubber ones. The combi-valves checked ok. The pump does come on when the engine is cold. This has become a real stump the chump issue.