Well, it's already little bit late to post in the forum because I have took off the BMS tuning box from car.
Long story short, since I installed my BMS tuning box in my 13 650GC, I just always get CEL in 2 or 3 days no matter I drive the car hard or not. However, since I took it off, even I have done several full open throttles, nothing came out on my dash and I have driven the car with our BMS box for few days, everything runs normally .
Guys, what's wrong with my car?
According to one of my friends who works in dealership and he scanned the CEL for me, my engine was just overheating with the bms box. There is no exact problem could be found.
Well, it seems okay for me but I just do not want to see the CEL on my dash constantly.