DanMan35

I drove my car to AHP on Monday to get their #4 head swap done on my car. Along with that I got the heads race ported and milled, I had headers installed with catted x-pipe and exhaust and everything was tuned.

When I picked the car up on Tuesday and drove it home 270 miles it was fine. I started the car today to take it for a drive and noticed the CEL light was on (for the first time). I drove the car to Autozone and had them plug in their reader and the car is giving:

Code P0430: Catalyst System Efficiency Below Threshold (Bank 2)

When I had the headers and catted x pipe installed I also had extension harnesses for the install and I'm assuming those were installed as well. Why would my car show no CEL for the first 300 miles after header install but now it's throwing a catalytic converter engine code?

What exactly does the code mean? Is there something wrong with my high flow cats or is it just the computer recognizing that something is different? How do I go about clearing the code and stopping it from returning?

The car is driving great! I don't notice any issues whatsoever.

jft69z

P0430 is checking to see if the cat is working basically. It is comparing the upstream & downstream 02 sensors to see what the cat is doing.

There are a lot of things that could bring it in, especially if you're using aftermarket cats. The GM document below lists a lot of info, code setting parameters, also mentions it may set with NEW cats (yours have more miles, but who knows). Those thresholds for triggering the CEL are set for factory cats though. As 'Unreal' mentions below, all bets may be off with aftermarket cats.

Unreal

Easiest way to fix it would be to tune it out. Cars with headers, even high flow cats on headers commonly get it, as they don't work exactly like the factory system wants to see.

DanMan35

^^ So I'm guessing that is something my tuner should have taken care of during the tune and either 1) forgot to do it or 2) did it but for some reason the CEL came back.

meanjoe

So I guess your tuner is 270 miles away? Did they tune it on a Dyno? You may want to find a guy with a Dyno closer to you so when these things happen you have someone nearby.
Mine did the same thing to me but it was much later on after the heads were done. I took it back to Late Model Racecraft and they fixed it no charge. No problems since. You might want to just clear it and see if it even comes back. I think AutoZone will clear it for you. At least it runs great.

Unreal

CEL wouldn't come back if the code was disabled, so more likely #1

Dan_the_C5_Man

The move should have been to skip the extension wiring and reinstallation of the rear O2s, tune out the codes in the PCM instead.

jft69z

Guessing you don't have HPTuners so you could have them email you an updated tune that disables all of the secondary 02 stuff? It would then be a simple matter of you dumping that update into the ECM yourself.

Undy

As I recall it takes around 6 or so key on/off cycles for this code to set. I find it odd that the tuner didn't turn this off. It's sort of PCM tuning 101.

DanMan35

^^ A really good shop with a really good reputation did it so I'm guessing it was just a rare slip up on their part. I'll get it taken care of

American Heritage

I missed the code by mistake when I did the tune. It was a brief slip of the mouse pad while in the car.
We already have the edited/corrected tune file with the cat code edited ready to upload.
We are setting up a time for the OP to meet with one of our associates in Vegas to upload the edited file.

http://www.americanheritageperformance.com/

*El Ocho*

as always, Kohle with the superb customer service......

DanMan35

Definitely. And I hope you don't think by mentioning your shops name that was my way of taking a swipe at you. It was actually the exact opposite. I anticipated maybe some people wondering if I had the heads done at a half *** shop and that was the issue so to nip that in the bud right off the bat I mentioned I got it done at AHP so everyone would know I got it done at a reputable shop.

American Heritage

No worries at all brother.
I didnt take any offense to mentioning the shops name. You had a question, posted up your information to help get an answer to your question. That is what the forum is for after all.
We just wanted to post up that we knew how and where over site occurred and that the tune file had been revised/edited to correct the missed code and was ready to upload.

If you ever need anything feel free to shoot us an email or give us a call.

Thank you again for your business.

http://www.americanheritageperformance.com/