p0420 Catalyst System Efficiency Below Threshold (Bank 1). Does this mean my cat is dead? I have a Vibrant Downpipe with High Flow Cat. Any help?

 

Sounds like the cat to me,
They mad extended the warranty on it
so you should be good if you just take it
in they should swap it out for free.

 

its an aftermarket cat so they won't cover it. Its a high flow cat but the system has been on for over a year with nothing and now it throws this code. I can clear it with a scan tool and it will stay off for a little while but will come back on. O2 sensors maybe?

 

Just use a spark defouler sometimes high flow cats with throw codes. You have 3 options.

1. Just leave it CEL sucks though.

2. Get it tuned out and this can be farely cheap just get the 99 ZZP PCM Tune they will tune that code out for you.

3. A spark plug defouler will meter the air that hits the O2 sensor this had about a 95% effective rating.

 

Nvm, saw the post before mine. Yes a spark plug defouler OR whats also called 02 sensor housing extension.

 

Front o2 sensor or rear?

 

It's the front 02 sensor, are you tuned? Can just delete the code.
If the cat was fucked it'd prob throw lean bank codes and ****.

 

P0420 is Catalyst Below Efficiency its the rear O2 Sensor it the sensor that lets you know the cat is not working properly.

This is the rear O2 Sensor that putting off the code.

 

Yeah you're right. multitasking fail lol

 

I know how it goes mind is on one thing typing another. I must do that about 20 times a day at work.

 

I thought the rear was there to determine a difference between the front and rear. The rear should show smooth patterns and the front should have a rough pattern. If the front is faulty it would show not a whole lot of difference which would make it seem the cat is not efficient. So shouldn't the front u2 be bad?

 

Nope po420 means that the rear isn't reading correctly in comparison to what the front is reading