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  1. #1
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    2C77 and o2 Issues, please help!!!

    Hello All,
    Wanted to reach out as I searched and found nothing. I currently have a 2C77 ses light come on with stock DPs. The code reads Lambda probe behind cat Signal (bank 1). I replaced it and the light didnt turn off even though I cleared the code. I went ahead and ordered another o2 thinking that the first could have been defective. I just replaced it again and cleared the code, but no luck it pops back on.

    So tonight I used the BT to clear the code and it lasted a few minutes, and I ran a diagnostic to see what was happening. For the first few minutes before the car is warm the voltage to the o2 fluctuates like bank 2 with no problems, but once its warmed up and you are driving around a bit the voltage flat lines and sticks at .41 volts. Any idea what could case this? The car is an 07 335i coupe with FMIC and DCI and no tune currently.

    The dealer suggested performing a software update, would that really help? Any ideas you guys have to help me diagnose this I would really appreciate it! Thanks in advance and sorry for the long post.
    -Chris

  2. #2
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    Have you taken any data logs to see if maybe your fuel trims or anything else o2 related might be failing?
    COBB AP ProTune by Bren of ///Bren Tuning
    Akrapovic DP | Helix FMIC | Alpina TCM Flash | Walbro 450LPH Fuel Pump


    "The moment money becomes your motivation, you are immediately not as good as someone who is motivated by passion and internal will." -A. Senna

  3. #3
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    I haven't yet. Any particular values I should be pulling in?

  4. #4
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    besides fuel trims like you mentioned

  5. #5
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    Click here to enlarge Originally Posted by Aced16 Click here to enlarge
    besides fuel trims like you mentioned
    Did you ever get your o2 problems figured out ? I'm having the exact same problems . Thanks
    2009 bmw 335i , E60 , FBO
    Click here to enlarge

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    I did, ended up having a defective DME! Got it replaced and everything works great now!

  7. #7
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    Click here to enlarge Originally Posted by Aced16 Click here to enlarge
    I did, ended up having a defective DME! Got it replaced and everything works great now!
    Oh ok. Thanks ! I hope that's not my problem. When I get it figured out I'll report back .
    2009 bmw 335i , E60 , FBO
    Click here to enlarge

  8. #8
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    Click here to enlarge Originally Posted by Aced16 Click here to enlarge
    I did, ended up having a defective DME! Got it replaced and everything works great now!
    I found out what my problem was with my 2c77 and 2c78 errors. I replaced bank 1 & 2 sensors 3 times , and that didn't fix anything . I started looking at the dme and noticed 3 pins were half the length of the rest of them . So I grabbed a small pair of needle nose pliers and and pulled on the brass pins , one at a time very easily until they were the same length as the rest of the pins in the dme . I then hooked everything back up and BAM ! All errors are gone and o2s are working perfectly ! I would like to thank everyone for there help , including WedgePerformance !
    2009 bmw 335i , E60 , FBO
    Click here to enlarge

  9. #9
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    Interesting, the pins weren't seated in the connector housing and I guess they were making intermittent contact. You probably could have pushed on the wire as well as pulled on the pin. Either way it's a great catch.
    Eppur si muove.

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    1 out of 1 members liked this post. Reputation: Yes | No
    Click here to enlarge Originally Posted by ajm8127 Click here to enlarge
    Interesting, the pins weren't seated in the connector housing and I guess they were making intermittent contact. You probably could have pushed on the wire as well as pulled on the pin. Either way it's a great catch.
    It was the actual brass pins that stick out of the dme itself , that I had to pull out. I'm glad that I was able to pull them out as another dme just isn't cheap and then having to have it programmed to the car.
    thanks Click here to enlarge
    2009 bmw 335i , E60 , FBO
    Click here to enlarge

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