iABS issue '04 1150GS. Advice greatly appreciated.

Discussion in 'GS Boxers' started by justinmlowe, Jul 10, 2013.

  1. justinmlowe

    justinmlowe Smokin' 'n 2-Strokin

    Joined:
    Mar 21, 2010
    Oddometer:
    6
    Location:
    Buffalo, NY
    Here's the story. I recently bought a 2004 1150GS. Last night I removed the J&M CB/intercom that the previous owner installed. After removing the unit I noticed a change when I turned the key in the ignition. The ABS light flashes fast for a second, then slow and I hear the ABS relay clicking with each flash. (I thought the ABS and gen warning light illuminated together before, I could be wrong) I don't recall hearing that before. When I drive away the ABS light goes off but I don't hear the clunk-clunk like I would before. A test of the brakes seemed to reveal that I do not have ABS in the front. The back does have ABS but it is loud and clunky. I have attached a video. Any advice would be great. Thank you.

    http://www.youtube.com/watch?v=mKQJ-sOQgp4&feature=youtu.be
    #1
  2. jsb223

    jsb223 ADV Rookie

    Joined:
    May 18, 2006
    Oddometer:
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    Location:
    Waco, Texas USA
    BMW 1100/1150 ABS system checks

    iABS fault codes

    These should be listed on a sticker supplied with the bike.
    Gen OFF, ABS ON = Only residual braking in both circuits.
    Gen OFF, ABS flashes at 1Hz = ABS not available. Pull-away test not completed.
    Gen OFF, ABS flashes at 4Hz = Only residual braking function available in both circuits.
    Gen ON, ABS off = rear light/brake light defective.
    Gen ON, ABS flashes at 1 Hz = At least one brake circuit without ABS.
    Gen ON, ABS flashes at 4Hz =At least one brake circuit in residual braking function mode.
    Gen AND ABS flashing alternately at 1Hz = Fluid level in Intergral ABS too low.Low-voltage

    Try and ABS reset according to the procedure in your owner’s manual.

    Full and fresh brake fluid is a given, do not skimp here. Do the maintenance or have it
    done at least as often as recommended by BMW.

    Front and rear micro switch test. They should click loud enough to hear them engage
    but this by no means is an indication of proper operation. Check for proper switch operation with a DMM.

    Get a DMM “digital multi-meter” and learn how to use it.

    Both front and rear switches as NC (normally closed) the opposite of typical motorcycle
    brake light switches. Therefore is they are engaged at start up, an ABS error occurs
    because of an open circuit in the system.

    Make sure the handguard is not touching the front brake lever.

    Make sure the metal tab on the rear brake switch is making proper contact with the rear pedal assembly.

    Check your front and rear brake switched again as MOST PROBLEMS ARE SWITCH RELATED!

    Test rear brake light bulb. If you are having problems and have an aftermarket brake light installed,
    put the stock bulb back in a test. Test the tail light element and the brake light element of the bulb.

    Check ABS sensor gaps and the “spoke rings” they use to sense wheel speed.


    Dirty sensors, sensor gap too large, debris, dirt, missing or damaged “ring” spokes
    can all add up to an ABS fault condition. ABS sensor gap 0.45...0.55 mm (0.018 ... 0.022 in) (front and rear).

    Battery condition, the bike starts fine, what’s the problem. If the battery voltage drops too much while
    starting it starts throwing ABS error codes from the get go.

    Pad condition. Although this has been argued back and forth, if the pads on either end of the
    bike are near the end of their service life, replace them. At least one person has claimed
    this fixed his ABS problem. More likely the movement of brake fluid through the system
    after the pad change fixed the problem but I digress.

    Try taking off both battery cables and touching them to each other.

    If all else fails, disconnect the battery and let sit for 30 minutes, reconnect battery and give it a try.
    #2
  3. justinmlowe

    justinmlowe Smokin' 'n 2-Strokin

    Joined:
    Mar 21, 2010
    Oddometer:
    6
    Location:
    Buffalo, NY
    Anyone know why upon startup I only have the ABS light flashing and not both the ABS and GEN light flashing together. (See video link in post #1)'03-'04 GS owners, what flash pattern are you getting when key is turned in the ignition? I'm questioning my memory now, but I seem to remember both lights flashing together until system initializes (3mph).

    If my memory serves me well, any idea what caused the changed. Also, when your ABS light flashes can you guys hear your ABS relay clicking with each flash? Is that normal?

    Thank you.
    #3
  4. HTSRocker

    HTSRocker odd one

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    That light sequence looks normal to me. Now what happens after you start the engine and pull out after a few yards?
    #4
  5. BluByU

    BluByU Been here awhile

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    Lost in America
    Charge battery, or replace battery and recheck
    #5
  6. XPatriot

    XPatriot Charges have been dropped

    Joined:
    Mar 26, 2006
    Oddometer:
    1,076
    Location:
    West Chester, PA
    My trouble-shoot sense makes me think something happened when you removed the CB/Intercom. Check anything you reconnected after taking it out - often the ABS warnings start with low voltage. Most would point to a battery going low, but if it happened immediately after some kind of electrical work, you might have a dodgy connection that is causing lower voltage.
    #6
  7. justinmlowe

    justinmlowe Smokin' 'n 2-Strokin

    Joined:
    Mar 21, 2010
    Oddometer:
    6
    Location:
    Buffalo, NY
    Thanks for the input fellas. I rode a hundred miles tonight and all seems well. I think I was just being paranoid or over analyzing things. This is my first bike with modern technology.
    #7