Hi,

Got these error codes on
2001 Audi A6 quattro, 6 cyl 2.8L

P0421 (Catalyst efficiency low-bank 1)
P0431 (Catalyst efficiency low-bank 2)
P1423
P0741

Need advice on the best way to deal with it one by one..

For P0421 and P0431 I would get the O2 sensors replaced and see if that solves the problem

For P1423 I would probably get the vacuum lines replaced

For P0741 Thinking of getting the solenoid replaced and change the transmission fluid while at it.

Hope I'm doing the right thing. Please suggest/advice.

Thanks!

 

You could try the 02 sensors, but it is common for the Cats to go bad on those cars, and you might be better off putting the money towards the new cats.

The P1423 might be some of the vacuum lines in the SAI system, but listen to your SAI pump when you start the car also.

For P0741, I would try to flush the transmission fluid, we have a kit for your car here.

http://www.raimotorsport.com/ATF-Fil.../01v398009.htm

 

Thanks for the tip and the link