BMW R1200 GS 2012 no brake micro switches

Discussion in 'GS Boxers' started by Panvezys, May 2, 2020.

  1. Panvezys

    Panvezys n00b

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    Hello,

    Just bought a used R1200 GS Adventure K25 Year 2012 and the current problem I am facing is that the brake light is always on. I have read about the problems with micro switches, however, on this bike there are no front and rear micro switches. Just wondering if it is normal or they should be present on all bikes? I was thinking maybe ABS unit has some kind of pressure sensor which detects increased pressure and switches the brake light on? Thank you for your advice

    [​IMG]

    [​IMG]


    Went for diagnostics:

    Erased all previous faults. One fault pops up:
    005E20
    Control circuit brake pressure sensor, front


    Have not found any information on the internet about this fault. It seems that the pressure sensor is faulty. Anyone had similar problem?

    Attached Files:

    #1
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  2. GS Addict

    GS Addict Pepperfool Supporter

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    The brake light is activated by pressure on the Hex/Camheads.
    Exception - non ABS models
    Check that both levers return to neutral/off position and are not hanging up.

    I would do a brake flush on both circuits to start.
    Then try to reset the fault.
    #2
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  3. Panvezys

    Panvezys n00b

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    What do you mean by hex/camheads?
    #3
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  4. GS Addict

    GS Addict Pepperfool Supporter

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    1200 air oil/aircooled to 2013
    #4
  5. Lead Wrist

    Lead Wrist Mehr Gelände Weniger Straße

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    '04 - '09 R1200 engines are commonly referred to as Hexheads (cyl head cover shaped as Hexagon);
    '10 - '13 R1200 engines are commonly referred to as Camheads (dual cam engines);

    Yours is '12 => it's Camhead... :thumb
    #5
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  6. Panvezys

    Panvezys n00b

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    Got it. Was starting to look for some hexagonal screws somewhere .

    Bled front and rear brakes. Tomorrow will take to a diagnostic guy to see if it helped. Really doubt it.

    The weird thing is, that when I disconnected ABS module connector, the brake light is still on. The system shouldn't see any sensors in my opinion
    #6
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  7. GS Addict

    GS Addict Pepperfool Supporter

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    Control is failsafe system. In other words, the ABS module gives an open circiut signal to the BMSK which activates the Brake lamp.
    So, pressure or broken wire activates the brake light.
    The same logic applies to non ABS models (the brake switches are closed and open to activate the lamp thru the BMSK)
    #7
  8. Panvezys

    Panvezys n00b

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    Makes sense. It is very difficult to find information about this particular fault and pressure sensors. From what I found, it seems that this particular pressure sensor is inside the ABS pump and it is hard to replace.

    Do you know anything about these pressure sensors?
    #8
  9. GS Addict

    GS Addict Pepperfool Supporter

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    Very little. Dark secret so far. I know Module Masters were having a hard time sourcing them and they are Pro's
    #9
  10. eri

    eri Been here awhile

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    the GS ABS module up to 2006 had problematic internal pressure sensors

    however your bike has a newer version which has largely been trouble free

    so i would be leaning towards a wiring issue and not an abs problem

    wiring is difficult to work through a canbus vehicle with 'reading' the fault codes stored in the bike's computers

    is there a bmw bike club in lithuania where you could perhaps borrow an after-market GS911 bike code reader to read? (korrected)

    failing that checking all the connectors between brake light and under-tank computers would be a good idea
    #10
  11. GS Addict

    GS Addict Pepperfool Supporter

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    GS922?
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  12. miker325

    miker325 Been here awhile

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    It's a new release from Hexcode. Designed for people with overly large fingers, like the ones who hit multiple keys on a computer when they really mean to hit only one. :p3rry
    #12
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  13. GS Addict

    GS Addict Pepperfool Supporter

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    I quallify foor this releease. Upgradding now.
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  14. Panvezys

    Panvezys n00b

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    I went to a guy who has kind of BMW Service type tool which is more powerful than GS911. So he was able to read codes, change from miles to kilometers, update firmware, etc.

    I wrote the code of the fault in the first post:
    005E20
    Control circuit brake pressure sensor, front

    Yesterday I went to him again, as I have seen that it is possible to check pressure of the brake circuits with his software.

    Please see video attached from the brake engage test:




    We first engaged front, then rear brake levers.
    It seems that the pressure sensor in the front is faulty. The pressure does not change when engaged, it shows -327.68 bar. Also, @eri, I checked the tail light itself. It has two live wires and ground. Both wires are active - that's why the brake light is on. I think the tail light wires comes from board computer if I am not wrong, I wasn't able to found any schematics for this model of GS.



    Also it seems module masters are not able to fix this problem, their answer to my email:
    #14
  15. eri

    eri Been here awhile

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    ok you're well ahead of me here

    pity the pressure sensors also are problematic on the 2007 - 2013 abs too

    they don't seem as problematic as the 2000? - 2006 version, but that's not much help to you

    unless of course it makes the 2007-2012 modules cheaper on the 2nd hand market

    and it's esp. an issue for the front abs cct, because that's the one that will save your ass!
    #15
  16. GS Addict

    GS Addict Pepperfool Supporter

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    The tail/brake light is fed from the ZFE triggered by logic.

    The fact the the sensor shows no signal tells me that it may be a connection problem - open circuit (vs an incorrect reading)
    If you have the skills, open the electronics section and find the 2 pressure sensors and follow the wiring for the front sensor to the main board.
    Look for a poor solder connection or loose connector or anything else suspicious.


    I should note that I have stolen motors from a '12 or '13 Ford Fiesta ABS modules to repair this generation of BMW module. Never needed to go further in.
    They are cheap on eBay.
    #16
  17. Panvezys

    Panvezys n00b

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    Hello,

    Can you elaborate on that repair? I am thinking of just finding used R1200GS and buying ABS from them and replacing
    #17
  18. GS Addict

    GS Addict Pepperfool Supporter

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    I shared the motor repair on a related thread in this site. I did not bookmark.
    #18
  19. Panvezys

    Panvezys n00b

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    Hi,

    I removed the abs module. From what I heard, the pressure sensors are inside it. There are many wires, 2 larger ones are + and 1 brown for ground. There are also a few thinner wires.

    Do you know how to check if the sensor is bad with multimeter? Which pins to check?

    Attached Files:

    #19
  20. GS Addict

    GS Addict Pepperfool Supporter

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    The sensors are in the module itself under the cover and are each wired the the circuit board.
    #20