P0240 Code indicates "Catalyst System Efficiency Below Threshold (Bank 1)"

Is it more likely the O2 sensor is failed or the Catalytic converter needs replacing?

Thanks,
Steve

 

year?

model?

engine?

mileage?

Here is my scattershot recommendation:

Step 1: clear the code and see if it comes back

Step 2: replace the O2 sensors. clear the code and see if it comes back.

Step 3: bite the bullet on the cats

-not an expert, just an enthusiast

 

You sure it is not a p0420 fault code?

What year , model & engine do you have?

 

probably the cat if you wanna try and get around replacing that try the 02 spacers, that code is a pain and the a** to get rid of

 

Some models have software update that correct P0420 & p0430 codes. Avk engines are on that list.
Again , what year , model & engine do you have?

 

2004 - A4, Quatro, 1.8T

 

Its your CAT. I have the same code! I installed the spacer from 034 motorsports this past weekend and the code went away. Keep in mind this is a temporary fix!