O2 sensor issue - stuck at 14.93 'sometimes'

langsbr

Captain
Apr 5, 2017
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07 335i 6MT e90
I have found the reason for a steady state cruise issue I've had lately, but not the root cause. During a long drive yesterday, I noticed that my bank 2 STFT would go to max, 34% I think it is, whenever throttle was applied, even light throttle steady state cruise. When the STFT was doing this, I noticed that the bank 2 O2 was stuck at 14.93 - even when in gear no throttle, it was stuck at 14.93, while the other went open air 239:1. It would then begin responding and functioning correctly, in line with the bank 1 sensor readings.

Is that the normal behavior for an o2 sensor that is going bad? It only has about 4000 miles on it, but I did have some bad injectors in that bank for a while - I guess it could have prematurely killed it.

I'm trying to figure out if I have an electrical issue other than simply a bad sensor, as I would have figured it would be slow to respond, or totally dead, but not stuck at a certain value intermittently.
 

langsbr

Captain
Apr 5, 2017
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07 335i 6MT e90
14.93 every time? Wonder if its faulty

That's the thing - sometimes it works fine, but when it doesn't, it gets stuck at 14.93. It could be faulty, but I had the stuttering issue with the old sensor (granted, I didn't check the logs to this degree before) which is what makes me think it could be something other than the sensor itself.

i have suggestion ... go intp inpa or ista and reset learned varients also reset adaptions... let us know how that goes

I'll give that a shot - how does that differ from reseting adaptions for lambda sensors in MHD and would that have an effect on it responding fine sometimes, and others sticking at 14.93?
 

Twisted Tuning

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Oct 25, 2016
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N54 and N55 Cars
That's the thing - sometimes it works fine, but when it doesn't, it gets stuck at 14.93. It could be faulty, but I had the stuttering issue with the old sensor (granted, I didn't check the logs to this degree before) which is what makes me think it could be something other than the sensor itself.



I'll give that a shot - how does that differ from reseting adaptions for lambda sensors in MHD and would that have an effect on it responding fine sometimes, and others sticking at 14.93?

as far as i know they both accomplish the same thing.