May 3, 2014
2014 Corvertte Z51
Hi All,

I purchased a Corsa Extreme Exhaust for my '14 Corvette C7 Z51.

I got it installed by CORSA at their headquarters in Berea, OH. So it was professionally done by them no issues at all.

After 3 weeks my check engine light came on i started to freak out. The code is P0430 CAT Low Efficiency. Can some please help me as to what i can do? Why this came on? Is it severe? It took 3 weeks to come on, its not like it was the next day after i installed it either.

I took it to the dealer they took off the check engine light and it came on literally 5 minutes after driving it.

Ive only had the car 4 months so obv the engine is fine but its SUPER annoying to have a brand new car and a check engine light and its driving me crazy.

Please help me as to what i should do!

PS the Corsa Extreme system is awesome but this is a pain.
If you have active OnStar subscription then you could also press the blue OnStar button and have them diagnose the Check Engine Light code for you straight for the vehicle.

The OnStar rep can also help you set up a service appointment at your closest dealership or give you directions to it if you like.

Best of Luck!
The Onstar rep is likely to give him the same info as he has posted on this thread, nothing more. Making an appt regarding an after market exhaust issue with a GM dealer could get expensive and might not resolve a thing.

I would go back to the Corsa folks and get their technical support to point him in the right direction or clear it up if it is even a possible issue with their exhaust. Air flow issues/changes can cause trouble codes like he has seen with the cat. I'm sure this wouldn't be the first time they have seen this issue if it is related to their after market exhaust. If it isn't then may be it's time for a appt at the GM dealer but they would be my first stop just in case. Could be just a bad cat or sensor as well.

By the way I had a similar issue with my previous supercharged sports car, O2 sensor causing the code, was an issue with an after market exhaust. They had a small add on fitting which they attached to the sensor mounting which eliminated the code.
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After-market exhausts on the C7 seem to often give check engine lights. Corsa is just one of them. From what I've read it seems pretty hard to keep them gone (and expensive). Good luck.
Thanks everyone for your help and input. I am very pleased with the corsa exhaust, just looks like something was set off either by the O2 sensor or the CAT and i am currently exploring all options. Hope it gets sorted out soon!
My guess is that the cats are somehow faulty on the car--nothing to do with the Corsas, but more to do with the factory exhaust.

This would be annoying, and Corsas are a great exhaust--I have them in my C6.

Did y do headers, and x-pipe, or replace the cats as well as the exhaust?
Here is some info on another Corvette forum regarding the same fix they did to my car when the after market exhaust caused the similar engine code to yours. The Corsa folks would know this trick for sure.... I ran that car for years after this non fouler was added and it was fine, no more codes. Not sure if I can post a link to another forum here. If it goes away just google spark plug non foulers and engine code, you will find lots of info on the issue and a fix. That is if it isn't actually a failed sensor or converter.

Spark plug non-foulers = O2 simulators not needed! - Corvette Forum
That reminds me. I had my o2 sensors removed before the cats to avoid this situation. I believe there are four sensors, and I now am down to 2 sensors--I think because the air is so hot before the cat that it trips some of the sensors sometimes when you do headers and an x-pipe.

This could also be a similar issue for you--maybe you're running for sensors when you don't need to be?
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