Thread: Oxygen Sensor/Catalyst

I had the check engine light on come on so I took it to O'reilly's and told me that it was the oxygen sensor and the catalyst. I really don't want to buy or replace the catalyst since it's very expensive. Do you all think that by changing the oxygen sensor the check engine will come off. By the way the guy at the store cleared the light for me but it came on a few minutes later.
The car does turn on fine and rides just fine, but the CEL is very annoying.. any suggestions...

No questions in the How To section.

Moving to the correct spot.

Thanks.

What is the exact code number.

We need that to try and help your further.

he didn't give me code # I'll go tomorrow in the morning and I'll give them to you all

yeah..get the codes.

ok they gave me the following code:

P0420

P0420 Catalyst System Low Efficiency= ECM, PCM.

Yup you need a new Cat. Bill will probably chime in. Gm warranty their original cats for 10 years or 80k so your cat would be out of warranty. Easy and cheapest thing to do is either replace it w/ a universal cat such as magnaflow and have a exhaust shop weld it on or if your state doesn't have emissions you could just put a pipe in it's place.

Could also be the down stream O2 sensor but probably the catalyst.

When I threw that code it was because of an exhaust leak before the cat.

IF you change your cat may I suggest:

ZZPerformance - Catalytic Converters #ZZ-CATC

AND

ZZPerformance - Ubend Delete #ZZ-UBENDD

The Ubend Delete isn't needed but while your exhaust guy is under there might as well...

Then don't use the ZZP one.. LOL I was looking for the Magnaflow cat to post the link to but couldn't find it on ZZP, 3800performance, or intense.... I am pretty sure I bought mine from 3800performance a couple years ago for $80ish. Usually a muffler shop wants around $120 (here locally) plus for an universal cat that's why I went with the magnaflow one.

I have passed emissions two years now with the Magnaflow cat.

Originally Posted by matt5112

ZZP cats will set the P0420.

Not if you get the whole downpipe with the add on, which basically acts as a defouler, to not set the P0420.