Uprev tuned, but still CEL
 

I've had my car uprev tuned for a couple months now. I've gotten it done through Z Car Garage. I have ARK HFC, and full exhaust. I just recently got the Service Engine Soon light to show up. I checked the code and its P0420, which usually has something to do with the exhausts/cats.

Is it still possible to get a CEL with an uprev tune concerning HFCs or could it be something else causing the CEL? Should I take my car to the dealer to check it out? I live in California so I'm afraid they'd say something dumb about me modifying the cats. Unfortunately Z Car Garage is too far away for me to just go to have them look.

Some codes your tuner can shut off show they don't show up again call them and see.

exhaust leak? cats issue??

I think he may have a bird in his tail pipe.:bowrofl:

I think he may have a bird in his tail pipe.:bowrofl:

touché !!! :icon18::roflpuke2:

Did they turn off your rear 02 sensors when they tuned the car? If not, that may be the reason for your CEL.

Same exact same thing happened to me today. Got it tuned at Z Car Garage as well...
I have cat back exhaust and test pipes. Drove it for about 4k miles and got a CEL today...

To add to this. I think they just need to turn off the light. But I'm gonna have them check for leaks and make sure that the oxygen sensors are intact. Going in Wed, will update then.