P1092 0000EB O2 Sensor Bank 1 pre-cat

[mendes9]

Hello, as the title says getting this code so I replaced Bank 1 Pre-cat O2 sensor but still same issue. Checked live data using ISTA software and O2 sensor voltage is fine for bank 1 O2 sensor. If I clear the code it comes back, however, I have to drive maybe 10 miles or so so the issue is somewhat intermittent. I'm going to replace Bank 2 sensor also but I don't expect that to solve the problem. The only other suggestions I've seen is to clear fuel adaptations. Any other suggestions would be appreciated. This is for 2006 X5 3.0 .

[ahlem]

Check the wiring harness from the connector back.

[andrewwynn]

OEM sensors? I had fits chasing pre cat sensor errors until I tossed the crappy knock offs

[mendes9]

Thanks, i will check the wiring with a wiggle test. Yes also these bosch oem sensors.

[upallnight]

Originally Posted by andrewwynn

OEM sensors? I had fits chasing pre cat sensor errors until I tossed the crappy knock offs

Sensor are reporting the mixture so they are fine. Why do people blame the sensor when they get a DTC that the engine is running rich or lean? The sensor is doing it job. You need to understand the lean, rich reason. I would look at the MAF. If the MAF is not reporting the correct amount of air going to the engine it could cause a rich/lean condition. If you do replace the MAF don't buy a cheap Amazon or Ebay MAF. Buy a geuine seimens maf.

MAF do wear out, it's a hot wire which over time may change its resistance value.

[andrewwynn]

I blamed the sensors in my case because they died a quick death MTBF of less than a year. Replaced under warranty at less than six months on first one and I replaced the set with Bosch less than a year after buying the supposed German inexpensive set. I learned the hard way O2 also included in the only OEM.

It's so easy to change the pre cat on M54 I took a gamble on $45/set vs $70@ literally less than 1/3 the price. Not worth 1/10 the price.

That being said, just as you described how MAF will wear and report the wrong signal, O2 sensor likewise can wear and report the wrong signal. Much harder to figure out since O2 is the boss and decides how much fuel to use.

If pre cat O2 is wrong and sets up for rich/lean you won't get a rich/lean error related to pre cat because it has no way to know. It assumes it's correct. You will get a rich/lean condition at the post cat sensor which the DME doesn't use for fuel trim but will eventually report a fuel trim error (which I've gotten many times with the cheap pre cat sensors before going back to OEM).

[mendes9]

Well I replaced both O2 sensors BOSCH oem, cleaned the MAF sensor, and using ISTA reset adaptations. 1st time I did that, followed the directions after a few minutes IDLE and everything was back to normal except now I have 4x4 brake light on {Update} anyone that resets adaptations a few starts later and magically went out.

Ok drove it a few miles and light is back. I will post below the error from ISTA. One note that is giving me a clue. After I did adaptations a few faults came up and I read them. One was P1071 lean on bank one. So do I have a vacuum leak? If it was intake rubber boot for example it would think it would be both Bank1 and Bank2 but it's only Bank 1. And the code that is constantly coming back isn't for a lean condition it's low voltage as though a loose wire or something. Maybe a bad fuel injector on Bank 1, but no misfire codes and car feels perfect idle etc,.? The O2 sensor code for low voltage has me baffled unless it's misleading. Suggestions on what to check?

Update 1: I did some more research and best I could find since it's only lean condition on Bank 1, is possibly a stuck DISA valve which would possibly make sense effecting only one bank of cylinders. I found many p1071/4 but not many 1071. I will test this next.

Update 2: I tested the DISA valve as shown herehttps://www.youtube.com/watch?v=pg6Jb3qEYvM&t=188s and the simple holding of the vacum line and seeing if the valve comes back works. I also did the 2nd test which is to apply 12 volts and the inital test I did worked. Everytime I applied 12v the flap would move until I ran out of vacum. After that it hasnt' worked again, although I do here the solenoid/relay click. So not 100% sure if it's the disa valve, it surely is not stuck though. I may buy a smoke machine and do a smoke test, although again why wouldn't I see lean condition on both banks? So many possibilities, including a partial clogged injector? I wish ISTA had graphing capability for fuel trims.

Update 3: As I was putting back the DISA valve, I noticed that one screw was missing. Humm, it's been years since I replaced it, was it not making a good seal? Although again why only on Bank 1? I also got some fuel trim and MAF data Fuel trim are within spec but strange as the numbers like never moved while looking maybe 5 minutes even accelerating of-course. I know connection is good as the Injection duration and Ignition timing values change in real time. I also looked at the MAF, that was also within spec besides inlet air temp seemed high at 122deg F and it's 80deg today and I'm in the shade. Besides that at idle and 2500 rpm MAF data was good. At this point I'm only getting P1071 code, but I need to drive it some more. Interesting is that it's not throwing check engine light but P1071 code was there when checked with ISTA for codes. The saga continues.

Update 4 [Fixed or so I thought]
So at this point I have driven about 50 miles and the Check Engine Light has not returned . So what was changed?
1) Both pre-cat oxygen sensors Bank1/Bank2.
2) Disa valve was removedand re-installed with 2nd bolt that was missing
3) Engine adaptations was cleared.

So what do I think actually resolved the problem? It is my believe that resetting adaptations actually resolved the issue. There is a chance that there was a small air leak from the DISA valve, however, when I pulled it even though there was one screw missing it appeared to have a good seal but I could be wrong. Anyway, I hope this information helps someone else.


Update 5 [Finally fixed maybe?]
Well, I thought it was fixed, but came back. After much research, basically, it's either the down stream O2 sensors, or the MAF sensor is the most likely culprit. I replaced the O2 the down stream O2 sensors and the mechanic money light "Service Engine Soon" came back. I then started to search for MAF values for this engine, I didn't find anything really good. ISTA also sucks as I couldn't find any way to graph MAF values over time. I'm looking into getting a scan tool to do that (autel ap200m is high on the list). I looked at the free frame data for the code and it's the same, and the long term fuel trims are at 10.2%. I found article saying anything above 10% usually throws the money light. Ok, next I smoked tested again, and everything is sealed up no leaks at all. I'm suspecting for sure the MAF is the issue, it must be a little off. Rather than buying another MAF, I tried a thorough cleaning of my MAF. Well after 4 hrs of driving now.. the money light has not RETURNED! :-) . So, either I needed a good cleaning, or its a combo of the cleaning and the new 02 sensors as I did not reset the calibration. I wish I had a before and after fuel trim data. Anyway, so far looks good, hope this helps someone else, if this is the end of it.