Did the most research I could to avoid writing this up...maybe wasn't good enough.

I have a 2011 G37 6MT Sedan.
So I recently threw on an ark grip exhaust and hfcs. Had it done by a reputable shop that has done the exact setup on a friend of mine too.

After a few days the SES came on...had the codes read and they were P0420/30.
So I reset the ecu and it helped clear it up...until three days later. Came on again.

I thought I'm going crazy so I reset again. Don't know if that did any harm or not lol but it came on once again.

Being a bit paranoid and don't want to consistently reset it every few days. Its been a few days since the second reset and the Ses has yet to disappear.

Friend of mine with exact setup reset once two years ago and never saw it again.

Am I doing something wrong?
Any help would be appreciated.
Thanks everyone.

 

Move to tech questions.....sorry

 

Any ideas anyone?