Guys,
For those of you that are getting the "oxygen sensor adaption limit," I might be able to shed some light in this check engine light error codes.
Here are the codes for the Oxygen sensor adaption limit;
Peake Research tool: E3 and E4
OBDII: P0188 and P0189
BMW DTC Code: 227 and 228
Explanation:
According to my research and the BMW master mechanic, basically your oxygen sensor is getting an abnormal reading. The abnormal reading will result in the sensor being unable to adapt beyond its +/- 10% threshold to adapt for the fuel/trim mixture. Therefore, either your car is going to run too lean (not enough fuel) or too rich (too much fuel).
Problems:
1) Either your pre-cats oxygen sensors are bad.
2) Fuel pressure regulator
3) Leak in the air intake /vacuum system
Since I recently replaced my pre-cats and fuel filter/fuel pressure regulator I knew I can eliminate problem #1 and #2. I knew I had a leak somwhere. My car is 5 yrs old and over time the various rubber boot/hose in my engine compartment is failing or will fail.
I did a visual inspection but couldn't determine the leak. Therefore, I bought my car to the dealership and explain my situation. The dealership conducted a vacuum leak and sure enough my car had a leak in the elbow rubber boot that is connected to my throttle body (see attachement).
Anyhow, if you are having the same problem you might want to start with your O2 sensor, fuel pressure regulator and the vacuum leak.
I hope this helps.
Charlie Six out!
I have a similar problem. I just replaced a set of o2 sensors just before the cats and still getting a CEL. I guess I could change FPR and check for vaccumm leaks. What would be an effective way to check for air leaks??
Sprays that ignite, start sprays etc. Spray it on suspicious areas and watch for RPM change.
A faulty fuel pressure regulator can cause those stored faults, but those fail extremely rarely. The usual cause is almost always a vacuum leak, such as the air boot in Charlie's case. V-8 engines, especially M60's, are prone to faulty intake manifold gaskets. Also on eights, the vacuum hose to the fuel pressure regulator tends to soften and fail. Another thing to check for is the rubber plugs on vacuum fittings, usually around the front left of the engine, or the rear of the intake manifold.
Fours have a problem with the crankcase breather hoses softening and failing. All models can have the rubber intake air boots fail. Sometimes they look ok on the top, but the fittings underneath where other hoses plug in are cracked. If there's any doubt about an air boot, it's best to remove it and check it carefully. Also the crankcase has to be sealed. Check the fill cap gasket, dipstick o-ring, breather hoses, etc.
One very common fault on all engines is the crankcase breather valve. I usually replace several a month. There were two last week, an M62 and an M52. It's one of the first things to check on any car with mixture or misfire faults. Simply, the crankcase vacuum should be between 3 and 6 inches. Any more, even an inch, and the vent valve is faulty. I use a slack tube manometer with an oil fill cap adapter to check, and it takes only a couple of minutes to hook it up and make the test. Sometimes spraying carb cleaner in the area of the valve will reveal a vacuum leak, but that isn't always the case, and actually measuring crankcase vacuum is the only sure test.
Anyone with mixture and misfire faults, who suspects a vacuum leak but is unable to locate it, should find a mechanic with the correct setup to check the vent valve.
Beißen Mein Wiener!
Here are the main part numbers needed for replacement
11-61-7-501-566, 11-61-7-504-535, 11-15-7-532-649
these can be foound on realoem.
for those of you who are burning oil as well there is a thread number 583950 which also talks about excessie oil consumption do a search for 330 oil leak at 25,000 miles
All the best
You use a man o meter, and you're checking for vacuum?
Where is a good place to put my regular old vacuum gauge? I got these codes a couple of days ago.
Hey Charlie, just wanted to say thanks for posting this up. We have had an issue with our car for years per this thread (http://forums.bimmerforums.com/forum...php?p=11602940) and the mechanics have never been able to fix it. I read your post a few weeks back and asked the mechanic to look for a leak on the intake end and it turned out to be a old, leaking vacuum hose.
The Check Engine Light has been gone for a month now, and the car has regained a significant amount of power.
Steve
2001 530i/5 S+P CDV delete/Akebono ceramic pads/M5 SSK/RedLine MTL/M5 rear sway bar
BMWCCA Member #337964
No offense taken... but at the shop I worked at, that's what we called it.
Is the emphasis on the "O" in
Man
O
Meter
coming through in this text?
(Like the Strength - O - Meter at the carnival or something).
It's starting to seem a lot less funny now that I've explained it so thoroughly.
the throttle body elbow is the most common place for leaks. seconded by the oil drain hose from the bottom of the CCV to the dipstick.
ASE and BMW Master Certified Technician
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