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Thread: Key fob

  1. #11
    Join Date
    Jan 2011
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    uk
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    847
    Quote Originally Posted by Mjolinor View Post
    Well I just powered a key up from a power supply and frequency does not drift at all. At around 2 volts it stops working.
    Which model ?

    Iíve read it somewhere (the freq shift thing), long time ago ... reputable source.

    The rolling code stuff etc is all legit
    You're so money supermarket and you don't even know it!

  2. #12
    Join Date
    Mar 2012
    Location
    Burnley
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    1,383
    450. I only have one key for my 451 so I aint about to use that.

    I have a couple of 451 keys somewhere, I will find one of those and look at it. This 450 key is using FSK, I don't think the 451 will be any different.

  3. #13
    Join Date
    Mar 2012
    Location
    Burnley
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    Datasheet for chip in 450 key.

    I can't attach it, the forum will not let me.

    http://pdf1.alldatasheet.com/datashe.../U9280M-H.html

    I think I read it in here somewhere a few years ago that bits were set for battery state but I can't find it now.

  4. #14
    Join Date
    Jan 2011
    Location
    uk
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    847
    Quote Originally Posted by Mjolinor View Post
    Datasheet for chip in 450 key.

    I can't attach it, the forum will not let me.

    http://pdf1.alldatasheet.com/datashe.../U9280M-H.html

    I think I read it in here somewhere a few years ago that bits were set for battery state but I can't find it now.
    More direct route to the sheet

    http://pdf1.alldatasheet.com/datashe.../datasheet.pdf
    You're so money supermarket and you don't even know it!

  5. #15
    Join Date
    Nov 2013
    Location
    Central Scotland
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    443
    Quote Originally Posted by Mjolinor View Post
    I replaced mine yesterday for the same reason .....It's so easy to write how to do it but it took me over 20 minutes to clip the goddam thing back together.
    Likely you got the rubber button pad membrane offset slightly and got it trapped beteen the two halfs of the key fob when putting it back together.

    You have to really watch that as you clip it back together, that nothing moves out of allignment.

    PS....thanks for the replies about key fobs. All this modern technologhy packed into a small car. Amazing

  6. #16
    Join Date
    Mar 2012
    Location
    Burnley
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    Quote Originally Posted by colin2x2 View Post
    Likely you got the rubber button pad membrane offset slightly and got it trapped beteen the two halfs of the key fob when putting it back together.

    You have to really watch that as you clip it back together, that nothing moves out of allignment.

    PS....thanks for the replies about key fobs. All this modern technologhy packed into a small car. Amazing
    I reckon the reason was that I did it in the car at zero degrees. It wasn't the rubber for sure because I tried assembling it with nothing in there and still could not click the two halves together.

    It is probably a good caveat to only do it at room temperature.

    There is more processing power in the key fob than there is on the Voyager spacecraft.

  7. #17
    Join Date
    Nov 2013
    Location
    Central Scotland
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    443
    Yeh, at freezing temeratures the rubber will be hard.

  8. #18
    Join Date
    Sep 2013
    Location
    West Midlands,England
    Posts
    56

    Just recently the battery in my 451 fob has needed changing more often. The car is not an everyday driver.

    I've put yet another battery in it and retired it while I use the 2nd key and see how long that lasts.

    I'm wondering if these fobs can develope internal faults that reduce the battery life or maybe the shelf life of my battery stock has expired.

    Merry Xmas

  9. #19
    Join Date
    Nov 2013
    Location
    Central Scotland
    Posts
    443
    More likely the shelf life of a battery, as I used to have an official spare smart keyfob battery for my 450 car when I got the car, but when it came time to replace it, years later, it was dead as mutton.

    I just buy those button battery packages out of poundland (has roughly 20 batteries with different CR numbers), and fit one of those CR2016's for the 451 Fortwo, and at least i know its a reasonably new battery.

    Merry Xmas and a happy New Year
    Last edited by colin2x2; 17-12-2017 at 03:04 PM.

  10. #20
    Join Date
    Mar 2010
    Location
    london
    Posts
    97

    Unhappy

    Just recently I have noticed that when I lock my smart with the remote ,I no longer see the three or four slow flashes although the car does lock. It does however flash twice when I unlock the car.


    My child lock works as soon as I drive off but the red light on the lock button does not come on anymore as it use to do.

    I changed both batteries but indicators still won't flash on locking... only works with unlocking.
    Last edited by classic123; 09-10-2018 at 03:41 PM.

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