The codes i pulled were:

P1131 B2-S1 HO2S
P1113 B1-S1 HO2S
P1423 Secondary air injection soleniod valve bank 1 flow to low
P1411 Secondary air injection soleniod valve bank 2flow to low

My question is are these fault codes related in some way? I checked the AIR soleniod and found a resistance of 23.5 ohms. Just below the specified value of 25-35 ohms which would indict that the soleniod needs to be replaced. Could it still be the actual secondary air pump thats bad since im getting faults on both banks orcould the faulty soleniod cus both codes? I have read that the air pump is a common problem with these cars.Also find it hard to believe that both O2 sensors would go bad at the same time. Could the bad soleniod or pump also cus a fault in the O2 sensors? Thanks for any help. Have learned alot from this forums

2002 A6 4.2 52k miles

 

Check for vacuum leaks in the vacuum hoses running to the solenoid valve and from the valve to the combi valves. I would also try erasing all the codes and seeing which ones come back. The faults could be related but i doubt they are.