LS1Steve

Had a P0420 come on every couple weeks recently. Changed the O2 and that seemed to fix it for a couple months. Now it is back again so I'm assuming the cat is bad?

What are my options for my CA car? What quality unit can I replace it with, while staying smog compliant? I know there are different quality levels and shopping cats is a maze...

ssbowtie1

What year is your car?

LS1Steve

2009, 14K miles

ssbowtie1

If your car is an early '09 car, it might be under this tsb:

https://www.corvetteforum.com/forums...ter-issue.html

See post #17.

Otherwise, just tune out the code, it will still pass emissions.

MTPZ06

^ Yep...I have an early build '09, and had it taken care of under that TSB for free when my emissions warranty was still in tact.

LS1Steve

If I were to bring it to a dealer to get the TSB update, would it mess with my tune?

ssbowtie1

I believe so. If your car is already tuned, just ask your tuner to turn off your rear O2 sensors.

Here's a thread explaining how:

https://www.corvetteforum.com/forums...s-ca-smog.html

MTPZ06

Yes, they will most likely flash over parameters in your current tune.. As bowtie mentioned...Kohle could take care of this on your next round of mods.

Mordeth

You don't want to turn off all the DTC codes and error reporting for all of the sensors like shown in that link. Below is mine. I gutted my cats with a metal rod and tuned out the codes for the rear 02 sensors using HP Tuners. It is simple and easy to do it. You literally just check a few boxes and change the error code to "No Error Reported". I've done it for most of my buddies modded C6Zs around here (for experimental and off-road purposes). Bye bye rear 02s and random errors!

LS1Steve

Just to clarify and make sure this is as simple as it sounds (if I were to do this myself, since I may not be back at AHP until the fall)....

I just need to buy HP Tuners, plug in and download my current vehicle tune, mirror to the adjustments above, save and upload the revised tune... good to go?

Looks like it is fairly pricey and might not be worth it since I'm not in there changing tunes often (at all). I assume any local vette owner with the software has limited licenses, so I wouldn't want to eat one of them. I guess the best bet is to find a local tuner to make this quick edit.

nuke61

Your clarification is correct. Also, if you can find a local HP Tuners owner, the cost of a license is ~$50, so you might be able to arrange a deal. Or explain to a local tuner what you want to do, it might be cheaper than you think to have it done. It's easy and quick enough that if you were local I'd just charge for the license.

ssbowtie1

Your previous tuner should be able to tune it out for cheap. Or if you come to socal I'll do it for you for the price of the license.

Just FYI...no one knows if California will somehow update their system to read data differently and be able to catch changes like these.

The 100% right way to do it is update your software by gm and retune, but people have claimed success with this method...at least for now.

427V8BB