I know this sounds dumb...

[Aceshigh4753]

Alright, so I've been doing a lot of reading on these boards lately and I have been learning a lot. You guys have a plethora of knowledge that is of great help to guys who are new to all this DIY stuff (Like me, I'm only 18 and I just graduated from high school :)). So, here goes my dumb question, if your engine is malfunctioning, but the check engine light is not on, will it still "throw codes" to tell you what is going on?

[Pirate_copy]

Not a dumb question at all

Yes it will buddy, as long as a sensor is playing up so the DME knows there is a problem

If it is a mechanical issue then sometimes it doesn't show the exact error but a symptom of it

[ashton540]

Yeah man, it's not really a dumb question cause I used to think that the check engine light was when there was a serious mechanical problem in the engine. The CEL (check engine light) usually only has to do with emissions. o2 sensors or even an gas cap not on all the way and stuff of that nature. So you could have a serious engine problem and not have a check engine light. And yes, it will throw codes or atleast it will usually show a symptom or culprit of a problem.

[Aceshigh4753]

Thanks guys. And I hear autozone will pull your codes for free?

[ashton540]

yes they will but I'm not sure if their diagnostics will read certain codes... In fact, I know they won't. So you should definitely just go to a dealer or a shop that has the equipment to do a proper reading. Because the indy that specializes in German cars in my area said his computer that they use to read the BMWs cost 14,000 dollars and will read every code and point out every last little malfunction on your car all the way to the horn. The one at auto zone costs a couple hundred bucks at most. If you have a check engine light go to auto zone and give it a shot. it won't hurt. If you want to know everything about your car and you have no CEL have it done properly. Just my $0.02 :thumbup: