Hi, guys, new here. Just got a 2000 A6 2.7 t, 125k miles. Good conditions. Love it. Timing belt was replaced at 85k and quite some suspension parts very recently. Just come to say hi and some questions.

The CEL is on with P1423 ( Sec.Air Inj.Sys.,Bank1 Flow too Low) and P0421 (Warm Up Catalyst Efficiency Below Threshold (Bank 1)). The car is running great so I think I am going to deal with them later. Any suggestion will be appreciated though. I cleared the codes before coming back home and the CEL didn't come onin the the 60+ miles of highway driving actually.

I don't have an ower's manual. Is there anywhere I can look for quick information before I get a manual? I know how to operate the car quite well now, but I always like to confirm that.

What oil does audi specify? The previous owner said he used mobil 1 5W30 and changed every 5000 miles, mostly highway long commutes.

What service manual do you prefer? Thank you very much!

 

Your P1423 code may be caused by a cracked or broken vacuum hose to the Secondary Air Injection Combi Valve. Just repalce the bank 1 hose, the one that is cracked or broken.


Your P0421 code may be a result of the first code. It says "Warm up catalytic efficiency below threshold for Bank 1", that same bank referred to above.

Fix the vacuum hose andP0421 may not reappear.

Cheers,

John