Hello,

I am attempting to fix my 2000 Audi A4 Quattro (V6) and hopefully get rid of the error codes that have been on there for awhile. Below are the error codes I have:

P1113 Bank1-Sensor1 Internal Resistance too High
P1131 Bank2-Sensor1 Internal Resistance too High
P1411 Sec.Air Inj.Sys.,Bank2 Flow too Low
P1423 Sec.Air Inj.Sys.,Bank1 Flow too Low

Has anyone encountered this group of codes before? It could be a bad O2 sensor, or carbon buildup on the EGR Valves, or bad vacuum hoses, or possibly 10 other things. Just trying to narrow it down.

The car seems to drive just fine, but it has a rough idle. I have tried clearing the codes, but they come back within 2-3 days of driving it.

Any advice helps!

Thanks!