All the cel means is that the rear o2 says things didn't really get warmed up in your drive cycle. A cheap code reader or a visit to AutoZone can scan and clear that. Then watch if it returns. I am always suspicious of low mileage performance cars. Tough to blame the oem when you don't know how the car was treated. I bet you find a lot of witness marks on bolts under that thing if you look.
2014 Premium GT, SGM, Brembo, Auto, Tech, Comfort, etc. GT500s, Steeda UCA, VMP auto tune, 100 shot on BBR tune, best et: 11.38 at 120.85
2012 GT, Candy Red, Brembo, 3.73, Tech, Comfort, etc. Procal tune, Roush upper, UMI LCAs, Steeda red bracket, GT500s, 28X10X16 Hoosier slicks, best et: 11.91 at 115.23 RIP