I did not go to the dealer with the aftermarket Y-pipe and exhaust with CEL on! I am pretty sure they would find it a convenient excuse to void my warranty. After going back to stock Y-pipe and continue with Aeries Ti exhaust (and code cleared), I did go back to the dealer for maintenance...
Just to give an update that after going back to stock Y-pipe, w/ Aeries Ti muffler, there has not been any CEL at all. It works smoothly so I will just keep the exhaust in place. Jason has been very helpful thru out the process. Wish they would make a straight pipe version with even louder sound!
I am having similar issues after installing the Ti muffler, decat pipe and Y-pipe. But my code is P139 and P159 meaning both O2 sensors are "slow to respond". I only get the CEL but no limp mode and it drives normally. My garage suspects that the Y-pipe has a larger diameter than stock and that...
My dealer just updated my V6 software 2 weeks ago. They told me some people using Shell V-power fuel still had issues after the update. He also added it has something to do with the latest Euro emission requirement and some of the newest BMWs and Mercedes also suffer from cold start issues...