5-Series (E12,E28, E34, E39, E60)Chat relating to the BMW 5-Series of all generations. Specific models include: BMW 518, BMW 520, BMW 520i, BMW 530i, BMW 528i, BMW 530i, BMW 518i, BMW 524d, BMW 525i, BMW 525e, BMW 528e, BMW 540i, BMW 535i, BMW 520d, BMW 525td, BMW 525d, BMW 530d, BMW 525i/xi, BMW 530i/xi. (BMW 5-Series Forum)
Help! I have a 2000 528i with 70,000 miles, my inspection sticker expired, I can't go get a new one because my "service engine soon" light came on, and I don't know how to fix the problem.
My code-reader reads 2 codes:
E3 ("oxygen sensor adaptation limit cyl 1-3") and E4 ("oxygen sensor adaptation limit cyl 4-6").
No other codes, and the car runs fine in all conditions. Tried resetting the codes but they come back.
I saw a thread from last year that talked about possible vacuum leaks causing the engine to run so lean that the fuel injection system can't compensate. I've looked at the intake boots from airflow sensor to throttle and found no leaks. I even replaced one of the boots because the dealer jammed it only half-way onto the plastic piece and clamped it down, and it seemed potentially damaged from the halfway-installation.
How big a vacuum leak is needed to cause these codes? Is a tiny hose with a leak enough to cause it?
Anybody else have experience with this?
Any suggestions are appreciated -- I don't know what to look at next.
I believe your problem is the sensors themselves. You have stated that your car runs fine, correct? Bad sensors can damage your catalic converter. You are also probably getting bad gas milage.
I replaced my oxygen sensors @ 78k miles. My car was running fine at the time when the light came on but I was only getting 12 miles per gallon... After replacing the sensors, I get 15 driving in traffic.
Hmm. Seems strange they went bad at the same time, and at only 70,000 miles (they're supposed to be good for 100,000 I thought). I tried to get the min and max voltage readings from my scan tool, but it's telling me "N/A" (even though it works fine on the oxygen sensors on my Jetta and my 911). So I wonder if it's the tool or the car or the oxygen sensors.
In the meantime, I cleared the check engine light, and it doesn't come back on immediately, so I successfully got a new inspection sticker today
The spark plugs are also supposed to be good for 100,000 miles. I wonder if I should replace them too. The original plugs are 4-prong, and the only 4-prong AutoZone has are Bosch Platinum. Should I buy those? I read someplace that Platinum wasn't "hot" enough for daily driving.
usually an adaptation limit fault is not a fault with the sensors themselves, but rather a lean or rich running condition. The problem with obd2 codes is they dont always tell you which it is. Obviously it makes a big difference in the troubleshooting. Find out if the car is running either lean or rich then troubleshoot accordingly. Replacing o2 sensors is not going to fx the problem in this case.
I can't lay hands on an oscilloscope to check my O2 sensors, but it seems dubious that they're both dead at the exact same time. My cheesy OBD-II program can't seem to get the min/max voltages of the sensors when the engine is running.
I now have a new lead though: I found a BMW SI # 110602 in the TIS program:
"The crankcase ventilation pipe can be damaged at the bend by chemical attack due to the formation of condensate from the acidic fuel and water mixture flowing through it.
"The chemical attack can lead to the formation of holes, through which the engine draws in secondary air."
It goes on to state that this could cause problems that would be caused by a leaner mixture, and can activate the "Service Engine Soon" lamp.
The part # for the crankcase ventilation return pipe is 11157520035.
So, next week I'm going to see if I can get to that pipe, remove it, and check if it leaks air.
The SI says this defect "is not contained in the official Defect Code Catalogue but has been included in the system, thus enabling warranty claims to be processed." Another secret-warranty item I guess.
It says at the bottom "Reimbursement is limited to 4 years/100,000 km and only possible until February 2004." I guess I could try and force the dealer to fix it for free (if that's indeed the problem), but I'm leaning toward fixing it myself rather than let them touch my car again.
As an aside, it sure is ANNOYING the way BMW tries to hide info as much as they can from me, making it that much harder for me to fix my own car. I see they sell info at bmwtechinfo.com, but they charge big bucks for it! And alldata.com won't sell BMW TSBs "at the request of the mfr".
I got my OBD scanner to read the fuel trim values, and long term fuel trim was +11.7% on both sides, indicating probably an air leak or bad MAF sensor.
I replaced the "oil separator" (crankcase vent valve) and all its hoses. I checked every hose on the intake side for a leak, taking many off and blowing through them with one end covered. Couldn't find an intake leak.
Finally I took it to the dealer. They did a smoke test to find any intake leaks (didn't find any), checked fuel pump pressure (3.5 bar, which they said is spec). Then they checked the MAF sensor output, which they said was "10HG" and should be "around 14HG". They swapped in a new sensor, cleared the adaptation values and went for a ride. The short-term (multiplicative) fuel trim went from +12% to -2% with the new sensor.
I told them to put my old part back on so I could fix it myself (save $250), which they did. In the end they charged me 1 hour labor. Very fair.
My new MAF sensor is coming this week. "Dirty_Tool" was absolutely correct on this one. The code description says the words "oxygen sensor" in it but the problem has nothing to do with the sensors themselves -- they just report the incorrect mixture.
To all and any who may be experiencing the same issues with 02 adaptation limit error codes E3 & E4, and misfires, I too had been wrestling with the same issue for two weeks. Made all of the common mistakes. Replaced 02 sensors, rearranged the coils, replaced the MAF, tried looking for air leaks, none of this remedied the problem. Only after I truly got aggressive and removed the entire air intake up to the throttle body was I able to find the root problem. The corrugated hose on the lower boot, the small one, had cracked in three places where it was bent over. This was where the air leak was occurring. Replaced the boot and haven't had any error codes since. $28.00
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