[nldave]

Hi folks,

I try to deal with a check engine light for the last couple of weeks. First of all I need to introduce the car I suppose.

Its a 330E from the year 2016 with 100.000 miles (160.000km) on it
all stock, nothing special
yes, its a hybrid
B48 engine
I fuel E5 which is common here in western Europe, its petrol with max. 5% ethanol added to it
Veepeak OBD ELM327 Bluetooth adapter

Im driving this car for a full year now while I've been used to driving diesel for many years (BMW F36 420D, E90 320D, E46 320D) and with this car I noticed the fuel consumption was a bit higher then expected. It started on 8L/100 on the long term BC from the previous owner and I managed to get that down a bit but never been to happy about it.

In the beginning I swapped out MAF sensor.. Didnt do a thing.. I basically gave up for like half of a year, just accepting the situation as it is. But, lately.. CEL popped up. I let it clear at the garage and asked if the spark plug refresh from five weeks earlier had something to do with that.. In which the mechanic replied that this would not be logical. Anyway, it was cleared and drove at least another 200 miles without this light on the dash. And then it popped up again.

I didnt wanted to go to the garage again so arranged ENET/OBD cable and ISTA because I couldnt read out or clear the light with an app. Maybe Bimmerlink paid version can do this, I dunno. Anyway, ISTA is working properly so; all CEL occurences (4x) happened at idle and at low ambient temperature (just above freezing point). I deleted the entries and the light didnt pop up anymore the whole last week but its a bit warmer outside so this can be the reason. I read about some faulthy winter mode but this cant be that because my car got all the firmware updates.

And.. I keep wondering why my fuel consumption is higher then expected. Plus, Im wondering why the back of the car is more black then I would like. Am I just seeing things or is the car really running too rich. The AFR of 14 wouldnt suggest that but is the whole story being told I wonder? Or worse, is there fuel leaking somewhere into the oil and is this the reason of strange idle readouts. High STFT at idle, especially after cruising, not so much after racing.

Main question. Is the behavior of O2S2 normal? I get the impression its not. What kind of app can do a proper log on this? I now screen recorded my phone (and recorded engine sound while driving as a bonus, hah).

many thanks for your time and sorry for the text wall

[laurentfy.lf]

Maybe faulty injector that remains open or leaks into the cylinder ?

[nldave]

yes.. I am also afraid of that. But how to diagnose that properly

I also got some comments somewhere else about the 900 rpm idle. This is too high for a B48? (its not recharging batt.)

[nldave]

finally got the second o2 sensor out. Replaced it for another one.

But, what the hell happened here?

[nldave]

I personally think we are witnessing a catalytic converter which is internally falling apart and the O2S2 lambda sonde had or has a part of the internals trapped against it.