09-25-2021, 09:16 PM | #1 |
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Any "how to's" about replacing an aft O2 Sensor?
So I got an engine light and my Carly reader says:
Code 12B801 - Heating lambda probe down stream of catalyst 2, Function: internal resistance too high. React Immediately. Looking for any "how to's" about replacing the sensor before I jump into it. ??? I'm also wondering that when I replace the sensor, will the "Check Engine" dashboard light go away or do I have to do something else to make that happen? Thanks in advance. Last edited by Walt White Coupe; 09-26-2021 at 07:15 AM.. |
09-26-2021, 12:25 PM | #2 |
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We chatted this one up a bit ago as I remember. A quick search on this forum will cover the process that some others helped me with and the subsequent discussions you and I had on the O2 sensors.
Remove the Air Filter Housings and everything is plainly visible. My suggestion is to replace these in pairs just like you would a bad headlight. I used an Autel Maxysis to reset the code. |
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10-04-2021, 08:52 AM | #4 |
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So I replaced the sensor yesterday and it took about 45 minutes doing it for the first time. I found some YouTube videos on replacing the spark plugs and those showed me how to remove the air box and expose the sensor. I ended up buying the ~$80 Bosch sensor rather than the ~$200 BMW original equipment sensor and by comparing the external configuration of the removed and the new sensor I found them to be identical. I'd bet that Bosch makes the original sensor also.
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10-04-2021, 01:34 PM | #6 |
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There was absolutely no operational indication that the O2 sensor was bad. It was only through the Carly fault reader that I found out about it. And it was quite a while before the check engine light came on after I knew there was an issue.
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10-06-2021, 07:44 PM | #8 |
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Drives: 2014 M6 Grand Coupe CP
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The primary, pre cat O2 sensor determines mixture (and affects MPG). The secondary, post cat is to monitor cat converter efficiency and functioning.
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10-06-2021, 08:32 PM | #9 |
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I've read that. And the reason I was in no hurry to replace it. But I've also read that it might affect air/fuel ratio depending on the individual system. Anyway, it was a piece of cake and cost me a total of~$90. I love this car.
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10-08-2021, 09:15 PM | #11 |
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Obviously the aft sensor is troublesome since BMW extended the warranty on 2014 and up to 10 years and 120,000 miles.
Last edited by Walt White Coupe; 10-08-2021 at 09:34 PM.. |
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06-09-2022, 08:54 PM | #12 | |
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Quote:
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06-10-2022, 07:09 AM | #13 |
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Once you remove the air cleaner on whatever side you going to change, the sensor is right there staring you in the face. You just need to buy the proper "sensor" socket. To see how to remove the air cleaners just look at youtube videos of how to change the spark plugs, because that's the first step in doing that. I couldn't find any videos that just showed the sensor removal, but it's just a matter of unscrewing it and routing the sensor wire.
For the socket, Google 22 mm O2 Sensor Socket |
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