2011 Bmw 328I With A P2098(2C32) Post Cat Lean B2 Code

Gilberto Diagnostician Texas Posted   Latest   Edited  
Resolved
Driveability
2011 BMW 328i 3.0L (N52) 6-spd (GA6-L45R)
P2098 — Post Catalyst Fuel Trim System Too Lean Bank 2
Engine Light On

hey was up guys , I've got a 2011 bmw 328i 3.0 n52 non turbo . with code p2098 (2c32) post cat fuel trim b2 . I've checkedthe following : -fuel trims are within specs , smoke test the intake , pressure tested exhaust and checked for leaks ,valve cover was replaced due to oil leak (dealer part) , i did update the ecm to the latest .

Nothing seems wrong with the o2 readings when i go test drive it , it usually sets after 4-5 drive cycles . asking for any suggestions maybe something I'm forgetting to check?

At this point I'm leaning towards a faulty downstream o2 staying stuck lean at times . code usually sets cruising at 2k rpm about 40mph its what it shows on the freeze frame . Usually with this code I find exhaust leaks near rear o2 flange but this car checks out good .

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Pierre Owner/Technician
California
Pierre
 

Sounds like you've done a lot of testing. Have you reset the Adaptions after the repairs? You most likely have a bad down stream o2 sensor.

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Gilberto Diagnostician
Texas
Gilberto
 

yes I've reset the adaptations multiple times . unfortunately i cant swap o2s from banks because they are different connectors .

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John Mobile Technician
New Jersey
John
 

What fuel octane is the customer using? Should be high test

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Justin Mechanic
Tennessee
Justin
   

The downstream O2s on this car, I believe, are the narrow band (zirconia) style. So, the computer is seeing a low voltage from this sensor and interpreting it as a lean condition. I suppose you could check that the sensor is getting hot enough to produce the correct voltage that the computer wants to see. That would be from its heater circuit and the actual temperature of the cat. I would try to…

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Gilberto Diagnostician
Texas
Gilberto
 

Will check temps and amperage pull from heaters

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Christopher Owner
Pennsylvania
Christopher
   

As long as trims are good I would say, based on your efforts, the sensor is bad. You could use a thermal camera and see if the temps on both exhaust banks are the same. This is tricky stuff, as a shop owner I am struggling and learning how to mitigate unbilled time. I am strongly against throwing parts at a vehicle but it is also very hard to bill all that diag in this case. I am finding…

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Justin Technician
California
Justin
 

If customer is told this o2 will fix it like too many writers do then usually ends poorly with a second estimate or third . Now I personally take over from tech to writer anytime I have a scenario where we are unsure and I speak honestly with customer . “ We use the manufacturer supplied trouble chart and that is , according to the BAR , is all that is required . Now we also search for Tsb and…

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Spiro Service Manager
New York
Spiro
 

Do both downstream O2 show rich during WOT on road test? May want to try propane enrichment and see if both O2 react the same way. Hope this helps!

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Darren Technician
Wisconsin
Darren
 

Sounds like a very small exhaust leak

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Rick Technician
New York
Rick
 

Just a quick check: make sure the O2 sensors ate all tight. I’ve had several BMW’s come to me with loose sensors.

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Gilberto Diagnostician
Texas
Gilberto Resolution
 

Thanks guys for all the help I ended up replacing the rear o2 sensor . That fixed it , all monitors ready no codes . Thanks again fellas

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Justin Mechanic
Tennessee
Justin
 

Great job

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