I have had this scanned by 3 different shops: one said nothing was wrong, the second said it would be manifold and cost at least $900, the third said oxygen sensors which I had him do. Only about 5 miles driving down the road after this repair was done the Check Engine Soon light came right back on. I am experiencing no performance issues whatsoever and the light is intermittent, a few days off, a few days on. I don't think it has anything to do with the gas cap because I only fill up about once a month and the light has gone on/off at least 6 times since my last fill up. I cannot afford a "science project" of having it scanned again, more repairs, then the light comes back. I seem to read that this has happened to many others. Can you give any advice?
check engine light on 2000 BMW 328i
by noramouse in North Palm Beach, FL on March 08, 2009
ANSWER by matte , March 08, 2009
This is a tough one. Check out the different stages of the Check Engine Light here: http://repairpal.com/check-engine-light The best thing to do is to find a shop that really knows BMWs--that should help take out the guesswork. The oxygen sensors is a good bet, as those definitely go bad in BMWs as they age. You could take it back to that technician, as they obviously didn't fix the problem for you. If the light is still coming on and going off, there's something else wrong, and I'm worried that if it's left unchecked, you could ruin those new oxygen sensors.
ANSWER by Mr Thrifty , September 01, 2009
This is three things: the valve cover probably (look for oil leaking onto spark plugs), the crankcase vent and or hoses, and the o2 sensors which probably need a clean.
ANSWER by lvidal , May 10, 2009
The gas cap is causing "check engine light " to remain on and needs to be replaced. Go to any BMW service or a Mercedes/BMW rapair service & have it replaced for $250.00 - $500.00.