Alright so my CEL came on about a month after i got the car (Ive had it for a year). Ive taken it to the dealership probably 10 times. Im not sure what codes its throwing. At first they would just reset it. They did this probably 5 times. It kept coming back on. Then they replace my O2 sensor. Still no luck. The dealer then asked me if i had added anything to my gas because my AFR was off and that is what was throwing the codes ( i think). Finally they reprogrammed my ECU and the CEL stayed off for maybe a week and then last night it came back on. I now have to take my car to the dealership again. This is really starting to **** me off. Does anyone know why my CEL keeps coming on or what would fix it. My car is an 05 and is completely stock.

 

car made on a monday? maybe some res gas? who knows.......i got no clue

 

well if they replaced the O2 sensor, it has to be one of those codes...

maybe you have a bad cat(i used to work on an assembly line, we got bad parts all the time, people are just too lazy to check them) or something that is throwing your afr off and causing codes, but i really dont know...and that is if it is an O2 code, and not know what the code is limits the thing which people can tell you, im just assuming it is the O2 sensor

good luck

 

x2 This would be my answer

 

may just need to be reflashed... it's a problem that does not really occur in the 06 models, but i remember hearing this before... it may be an older car, and when GM came out with the reflash your car may not have gotten it... i would bring that up to your dealer... usually fixes the problem right away

 

Ask your dealer to check for TSB's regarding a new flash program for your PCM. I believe there have been two updates since the 2005 model. I don't know if that's the problem, but it's what I got.

 

Ok guys i found the code. It's the P0171 code. I have a paper here that says that the code is still under investigation, but this was back in March. It also says that it causes no engine performance issues.

 

bump..