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1992 850i Trans fail safe mode

Discussion in 'E31 (1991-1997)' started by 92850i801, Mar 22, 2008.

    92850i801 guest

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    Just replaced my HP-24 trans and car still in trans fail safe mode.......:mad::mad::mad:
    How do i reset this or what must i do
    • Member


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    The "trans fail safe" mode can be caused by many problems, most of which are NOT related to the transmission. (In fact, the most comon cause may be weak batteries. Number two is probably ignition problems.) Was there a specific fault with the transmission that required replacement?

    You can force a reset of ALL memorized values and codes by disconnecting both batteries for about an hour (caution: you will need the radio unlock code and the engine will probably run rough until it "relearns" all the adaptive engine management values when you drive it again). Alternatively, you could disconnect just the EML unit (saves the radio, but engine will still need to "relearn" how to run).

    If the "trans fail" message comes up again, then you haven't corrected the source of the problem. An error code reader (like the Peake tool, or similar unit) may provide a clue.

    My 8 series is a manual, so I can't offer much help with the automatic. Good luck.
    • Member


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    Suggest you go here

    and use the search function at Roadfly. Lot's of info on the 8 series and this problem in detail. I have a 1995 850 Ci so the procedure is different.

    Good luck and let us know how it turns out.

    - Scott


    hipshot guest

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    trans fail safe

    I pick my car up tomorrow from dealer with same issue. @ 100k miles + spark plug leads and points need replacement. The diagnostic won't tell you which spark plug but will tell you whihc bank so you need to do the entire bank...700 bucks....sigh.
    You may be able to do this yourself, but getting at this part of the engine on an 8 is a bear.

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