540i check engine light turned on and don't know why

Everything seems fine with the car and there was a small raddle right under the drivers seat before the light came on. I floored it a couple of times to about 40 mph, and then soon after that the light came on but car still seems to run fine? Just wondering if anyone had any ideas of what could be wrong. I also did one start where i power braked the car because i have an automatic and wanted a fast start and i was wondering if that is bad for the car or if that could have caused any problems? My car is a 1997 540ia with 102,000 miles

It could be that your gas cap is not on tight or the famous O2 sensors and malfunctioning

Take your car to your local dealership, they'll be able to diagnose it accurately within half an hour and are relatively cheap, there are so many functions peformed by the ECU on these cars, that any other diagnosis you obtain will be pure speculat, These cars will stand the kind of abuse that you describe, but i wouldn't reccomend it as you can strip vanes off the torque converter, and they are an expensive box to rebuild

you can get your car to flash the fault code on the check light. look on bmwe34.net for how to do it. saves you the cost of a dealer connecting it to a computer and you can then look up the fault code

Take your car to your local dealership, they'll be able to diagnose it accurately within half an hour and are relatively cheap, there are so many functions peformed by the ECU on these cars, that any other diagnosis you obtain will be pure speculat, These cars will stand the kind of abuse that you describe, but i wouldn't reccomend it as you can strip vanes off the torque converter, and they are an expensive box to rebuild
mmm relatively cheap????? my dealership charges 100 dollars just having it in there garage on top of that around 80 dollars for hooking it up to the computer :shakehead Try a local autozone if you live in a area with this store free to checkengine light then go from there

Have you figured out whats wrong. I am looking to buy a 98 540 but the check engine lights on but it runs fine. I dont want to buy a faulty car.

BMW's post engine service lights prior to any problem. I have received a sign on my iDrive system saying "Coolant Level is Too Low". I was able to drive it for a good three days without a problem. Its just a suggestion so nothing worse happens.

I often find myself mezmerized by some of the things I read on this Forum !!! It's the main reason I decided to contribute once in a while, hoping to disspell misconceptions and some of the wild 'hand waving' ideas I was reading. This thread drives me to respond again.
To: 'luxuryracer4'.....At least have the codes scanned for fault[s]. The 'CHECK ENGINE' Light really does come on for a reason!!!!! The system has noted a sensor input [usually] that is out of a CAREFULLY predetermined range. It may only be a momentary 'glitch', maybe sparatic, maybe erronious
BUT on most all '90 a later BMW's [any car for that matter] they're fairly accurate at registering a failure that may or will lead to Catalytic Converter damage or complete failure. THIS IS ACTUALLY QUITE IMPORTANT THESE DAYS. Continued operation with a high HC causing problem WILL OVERHEAT and destroy the converter substrate, etc
leading to continuing 'CHECK ENGINE' illumination as
[since OBDII of '97] testing Cat. Conv. Efficiency is part of the system. The car will NO LONGER past an emission test in many states because if that fault code alone. AND CAT. CONV. REPLACEMENT IS RATHER $$$$$$$VE! !...Have it checked, please.

NO ENGINE CONTROL SYSTEM I KNOW OF CAN
'post prior to a problem'....they're not psychic!!
These are cause/effect [not affect] issues. They're
not 'suggestions' but STATEMENTS. SOMETHING IS WRONG,...PLEASE CHECK IT OUT NOW ! ! [before you do some serious, expensive damage]
I have had to replace M50 engines for people who ignored the "car's suggestions" and melted them down well before three days of driving.

IF YOU SEE A WARNING LAMP/DISPLAY, at least yake a couple of seconds and take a little peek.
they can't "tell" you HOW BAD the problem is, but can tell you it's likely THERE IS a problem..........jb.