During a recent 200 mile trip my 04 Mini S thru a code. Turns out to be p2096, which is determined by post cat o2 sensor. Bentley service manual says this o2 sensor monitors the cat converter for problems with the cat. If my catalytic converter is bad, how will that cause the ECU to call for less fuel. The lean condition does exist, it is easy to tell from my white exhaust tips. The car has 82,000 miles and has had an odor recently of a bad converter. What puzzles me is how the post cat sensor tells the ECU to trim fuel due to a bad converter. This is a rather technical question, but there are some very knowledgable people here or those who have sorted out this experience of their own. Looks like a header w/cat may be in my near future, but I like to understand how things work before I do that. Jim

 

i read it to mean the cat is leaning the exhaust too much . not the engine . it indicates the cat is malfunctioning . just my take on it .
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the dreaded P2096

you need to reset the adaptations 2x

it got rid of the ones we have had. Only way to do this is to have an autologic tool or go to the dealer

 

Thanks for responding. My concern is that I will hurt the motor running so lean. When you consider that my exhaust has turned white it would seem that there is not enough fuel getting to the cylinders. Resetting the adaptations 2x, wouldn't that be treating the symptom not the cause? the dealer is 150 miles away, so I'll see if I can pickup an autologic tool. When a cat converter goes bad does it get so hot it burns all the exhausted fuel flowing through it to the point that the exhaust tips turn white. Just trying to get a feel for cause and effect.

 

Well picking up an autologic tool is out of the question after looking it up. But my local BMW dealer probably has one. I'd like to determine and fix the cause of the the code error.

 

it's been a software error, not anything mechanical that usually causes this code. We have found this on bone stock cars and the dealer could never fix it. We have reset the adaptations 2x and it has never come back.
Good luck

 

MyFastMini: trust in him. He knows of what he speaks.

 

No question about that, and I appreciate how Jan monitors posts to help folks quickly. I wish I understood software and its relationship to sensors better for sure. But back in my day we turned screws on a carb to adjust air/fuel mixtures. While Jan's answer is accurate and succinct, my understanding is no better for it. The reason why after 4 yrs of driving a car with no ECU problems, and then 1 day the ECU decides to leanout the amount of fuel it feeds. Inquiring minds want to know the how and why. Jim

 

wow so it is changing fuel ? i thought pre- cat did that ...

 

I believe it is. Like I said the exhaust tips are white instead of thier usual black. Also when I monitor the instrument readout for constant MPG it will only go down to 13mpg when I stomp on it, it used to go down to 7or8 mpg prior to the SES. Overall the car still runs good, though it does feel down on power a bit.