threw up the code p0422. i have a 99 a4 2.8q. the code says main catalyst below threshold. how hard is it to replace the oxygen sensor on the main cat? any DIY? thanks for help

 

no one has had to replace the main cat o2 sensor??

 

Hold on there buddy, the main cat O2 sensor makes no sense, there is a before cat O2 sensor and after cat O2 sensor which one are you talking about?
Second the code for the catalyst below threshold means the cat coverter is bad not the O2 sensor.
Ask questions about the code if you don't know what your talking about.

 

my bad i wasn't thinkin straight, does anyone know what exactly a p0422 main catalyst under threshold bank 1 code means?

 

It means exactly what it says, the O2 sensors are measuring insufficient functionality of the cat converter. When you get that code there is only 1 repair, replace the cat converter.

 

How many miles are on your car?

 

95k

 

Yeah 99 times out of 100 its the cat/s. If its anything like the v6 passat its no driveway job.

 

Im assuming he's asking that because if you have less than 80k miles federal emmisions warranty would cover the cat converter. Since you have 95k your gonna have to pony up the dough.