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O2 Sensor Codes

7K views 19 replies 11 participants last post by  reynaldo 
#1 ·
I just replaced my Intake Cam Sensor with the D.I.Y guide on my 2000 323i and the car doesn't stall anymore. I also got the Peake tool to reset the ECU because of the CEL. Now Im throwing some O2 sensor codes:

E3- O2 Sensor Adaptation Limit Cyl#1-3
E4- O2 Sensor Adaptation Limit Cyl#4-6
CA- O2 Sensor Control Limit Cyl#1-3
CB- O2 Sensor Control Limit Cyl#4-6
97- Precat O2 Sensor Short to Ground Cyl#1-3

Do these codes mean I need to replace all my O2 Sensors? I wanna make sure this is the main problem before I go out and buy the parts. I still can't pass smog. Any help is appreciated. Thanks

Rob
 
#3 ·
How can I check for vaccuum leaks? Any common areas? Thanks. I have 116,000 miles on my car. I got a quote from checker and the bosch precat sensors are going for $150 each. I will try to replace the fuel filter as well.
I just wanna pass smog :cry:
 
#5 ·
Mine was throwing O2 sensor codes, mechanic found boot after MAS was leaking and the idle valve was stuck, ran a little over $400. Went to a good non dealership shop. They recomended a smoke test to see if any other vacum leaks, didn't do that, but after several months I have had no codes at all.
 
#6 ·
Thanks guys..I purchased a new fuel filter, a MAF Hose, and Cleaner at the dealer along with some fresh NGK Plugs. I found a D.I.Y write up here and I'll be working on this tonight. I'll be ordering the O2 Sensors at that website as well. Thanks again.

Rob
 
#7 ·
Any updates?

I've been having the exact same issue.

Same codes with the Peake tool:
E3
E4
CA
Cb

In the past week I've replaced:
All 6 spark plugs with Bosch Platinum+ 4
New oem coil boots
BOTH pre-cat o2 sensors with oem sensors.
BOTH post-cat o2 sensors with Bosch sensors.

Reset using the tool, drive 20-25 miles and the same codes come back.

Pulling my hair out trying to figure this out as I'm due for smog inspection on Monday the 1st and the police near my office really enjoy handing out tickets for inspired stickers since I cannot currently pass.
 
#8 ·
I still have the same codes E3,E4,CA,Cb...except 97 which seems to be resolved. I replaced the plugs,cleaned the maf, replaced the intake hose, replaced both precat bosch O2 sensors, new fuel filter, Oil change.

It gave me another set of codes with a cylinder misfire on #1 #2 and #3. Im gonna reset the CEL and see if it comes up again. :censor: I can't find or hear any vaccuum leaks. Last resort is to take it to the shop tomorrow. Or trade it in for another car. :cry:
 
#10 ·
Yeah this sucks. I forgot to mention I also replaced the intake Cam sensor and got a new Gas Cap at Desert BMW. It solved the other problems I had earlier. Now Im down to these 4 codes. :banghead:

I've been searching and found some stuff online that might hopefully solve the problem. I will check these out first before I give in and take it to the dealer this week.

Found this on another thread: Copied and Paste

" Dirty oil will not cause fuel mixture faults. Check the Crankcase vent valve (PCV). With the engine idleing crack open the oil filler cap just barely. If there is a lot of vacuum holding the cap down or the motor starts making a strange whistle/honking noise the valve is bad. Have you checked the throttle boots for tears? You have swapped the Air flow sensor. These symptoms sound like a bad air flow sensor. Have you put new front O2 sensors in the car?"

and

"Just wanted to follow up for anyone that finds this post through a search. The problem ulimately was that the "Idle adjuster" broke. This is number 7 in the attached pic and slides into the side of the intake manifold above the throttle body. The base of the door/gate that rotates to open/close the airflow broke off the the stub that operated it. This was causing a vacuum leak directly into the side of the intake manifold. When I bought a new one at the dealer (~$215+ tax) I was surprised they had it in stock. The parts guy said they had 18 of them on the shelf! So appearenly this is a common thing to break. Two screws and one electrical connector. About a 5-10 min job to replace it."

 
#13 ·
:censor:! No luck yet. I added some SeaFoam to the CrankCase and Fuel Tank and the car seems to be running a lot smoother. But the CEL came on again after 5 miles. It would usually come on within 2 miles.

Its down to either replacing the PCV or the #7 Idle Adjuster. I researched the DIY on the PCV and looks too complicated. I can't work with tight spaces. :banghead: The intake boot alone was a PITA. How much would the dealer usually charge for this? I don't hear any leaks and the car idles just fine.
 
#15 ·
Have a look for a detailed how-to post about smoke testing written by Seth from jbeurotech here on the forums. It reads as a little complicated if you're not experienced, but it is not a very difficult procedure. If you cannot do this test properly yourself, save yourself some money and have an experienced tech take care of it. Throwing money at replacing parts that may not necessarily need replacing is not the right approach.

One of the benefits of the BMW specific codes you guys are getting with the Peake tool is that you see exactly what BMW wanted their techs to see. For vacuum leak issues, however, more testing is necessary to find a leak. Having the best codes is a great way to start, but it is just the first step in truly diagnosing the problem.

Seth is very knowledgeable and experienced, and his posts should help you narrow this down.

Good luck!

Ken
 
#16 ·
E3- O2 Sensor Adaptation Limit Cyl#1-3
E4- O2 Sensor Adaptation Limit Cyl#4-6

any updates on these codes? Anyone
 
#18 ·
done all of them, even replaced a broke/faulty PCV....Still got those 2 codes....i wish i could find a smoke machine, but geez no one in my area has one and half of them look at me like im crazy for asking..haha
 
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