Soft close only on Boot/Trunk lid

Discussion in 'Electronics' started by rossy, Apr 5, 2014.

  1. rossy

    rossy Hardcore MB Enthusiast

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    Everything else works a treat but after the wife used the button i.e. not the remote to open the boot the soft close has stopped!
    It does not have full closer, i.e. click the remote and the boot springs open but you have to manual close it but then soft close grabs and pulls it down.

    When I say wife used button I mean the one near the number plate where you would put the BLADE KEY to manual lock...

    I believe I've checked all relivant fuses...
    :wallbash:
    CL55 AMG 2002, both doors soft close fine.

    Thanks
     
  2. def90cars

    def90cars Hardcore MB Enthusiast

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    Divorce would fix it, but that means you'll have to wash, clean and cook.
     
  3. V12

    V12 MB Club Veteran

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    The pump has a time out function to stop the vacuum system.

    Either the microswitch in the mechanism has failed (unlikely) or your pump needs adjusting/ is on it's way out.

    Test by activating the soft close on one of the doors and see if it pulls it in then immediately releases. You'll notice the door pops back out ever so slightly. If the time out function isn't operating correctly then it will keep trying to suck the door in more and more and eventually release after about 20 seconds. You can also test by putting your head in the passenger side of the boot while someone does the door. Listen to the pump. A successful operation will have the pump run for a couple of seconds and no more.

    This eventual 20 second or so release happens when the smart electronics realise that the pump has been running too long and cut it before it cooks itself.

    The computer will then keep count of the failures to self time out, if this happens just once it will ignore and still keep the soft close function but once it has happened 10 or so times it will disable that branch of the vacuum pump as it presumes it has a leak.

    By removing the fuse from under the seat and refitting it you can reset the count. Using star to clear the fault codes also resets the count.

    If you're handy you can remove the vacuum pump from the boot and open it up. Inside is a little thumbwheel that can adjust the vacuum pressure needed to activate the timeout function.
     
  4. OP
    OP
    rossy

    rossy Hardcore MB Enthusiast

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    Don't understand....both doors are fine its just the boot...so is the pump only for softclose on the boot?
    Sorry...but not sure what you mean by time out and you've only mensioned door not boot?
     
  5. V12

    V12 MB Club Veteran

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    The soft close branch for the boot has probably been electronically disabled so you can't test that function.

    The same pump also works the doors in the same way so you can test that as I described to narrow down the possible cause of the fault.

    If the doors work perfectly and cut out immediately then the pump won't be at fault and you will have to look at changing the boot lock mechanism.
     
  6. karozza

    karozza Hardcore MB Enthusiast

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    Another easy way to check if the vacuum boot latch is working correctly;

    1. Disconnect consumer battery in the boot for about 10 seconds; this will re-set soft close pump for the boot.

    2. Soft close boot, at the same time, put your ear close to the lock & listen.

    3. Now, you should hear the hissing noise from the latch stop just a short time after it pulls it shut.

    4. On the other hand, if you keep hearing the hissing noise from the vacuum suction for about 20 seconds after pulling shut, this means you have a leaking boot latch mechanism which needs to be replaced.

    The boot soft close feature will stop working again eventually so the vacuum pump will protect itself.
     
  7. V12

    V12 MB Club Veteran

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    Pulling the fuse will do the same reset as disconnecting the battery I believe.
     

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