Brake Failure!

[devauxb]

Had a 'pucker moment' yesterday evening when running errands. Pulled on the front brake lever and woh-mama nothing happened. Really pulled on the lever, got the bike stopped, got composed and saw my 'Brake Failure' light flashing rapidly. Powered the bike down, waited a moment and re-started. The Brake Failure light flashed slowly for a second or two and then went back to the much faster flash mode.

No clue why this would be happening. Working flawless up to now, then this out of the blue.

Servos not whirring (or working), I nursed the bike home on residual braking and parked it. Started it up again this morning sort of hoping that the bike had come to its senses overnight, but no go - same thing.

So, does this mean that I have just bought a $2300 or so controller?

Are there other things that could be the cause? I did a brake flush last fall and all has seemed fine until now. I haven't pulled the fuel tank off to look at the fluid levels in the controller - could this be a possibility? Fuses all look OK. Should I disconnect the battery/pull a fuse for a while in an attempt to reset the module?
Is there a diagnostic sequence I should follow before making my way to the dealer?

I'm thankful that this occured in a situation where I could maintain control and close to home. Nevertheless I'll be really bummed if I have to spend 1/3 to 1/2 of the bikes total value getting this fixed, ....

[Brettendress]

I'm having the same problem with my 04 1150 GS. Except for the fact that the brakes still work but a lot of times those lights are blinking like crazy and I shut it off and start it and it works again. Let me know what you find out, getting a little worried. 67,000 miles what could be wrong? Sensor?

Brett Endress
Altoona PA

[jingdog]

PM von Baden he will tell you what the problem is. It might be something simple like low brake fluid level.

[55380]

I had a similar problem with a 2002 R1150RT. The cause was low fluid in the servo. Yes, that is under the tank. I dislike having to pull the tank for such stuff that should be "frequent check" items. But, I have become accustom to pulling that tank. It is not really so difficult.

Be careful with the DOT 4 fluid. It is aggressive when in contact with paint. The BMW brand appears to be especially so. If you did run the servo low on fluid it will require bleeding. There are some good web instructions on how to do this. Be prepared for a slow, careful weekend effort. This is not a quick task.

Experience is a good teacher. "To be old and wise one must first be young and stupid".

I have the "old" part down. I guess I need to get around to fixing that "stupid" part someday.

Good luck on your brakes,
Pete

[kioolt]

Check to see if the brake light is always on. You may have something as simple as a stuck brake switch.

[Blacque Jacque Shellacque]

The bike will tell you if the fluid in the iABS modulator is low. The lighting sequence of the general warning lamp and ABS lamp might be helpfull.

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



paul

[devauxb]

You all were very helpful, thanks! I am much relieved that it was a simple fix.

It turns out that it was a stuck brake switch:

Check to see if the brake light is always on. You may have something as simple as a stuck brake switch.

I actually checked that and had convinced myself that I heard a 'click', but went back to it after eventually seeing that my tailight looked noticeably brighter than it should have (ie brake light on).

Of course, I didn't discover that until AFTER I had pulled the plastic and tank off. The reminder of the light sequence is helpful and if I would have read it closer, it would have probably avoided me having to go through this. Oh well, at least I got a 'visual' that the ABS reservoirs levels were OK; since I did the full fluid flush and fill in the fall (*boy that's a lot of 'f' words in one frase and doesn't even include the one I used when I had my 'moment'*), I kind of wanted to see if the levels were good. Plus, I did the fuel filter replacement - so all was not lost.

So, I broke my own mantra of 'check out the easy stuff first', but no biggee.

Now, I have to research a bit to see what kind of maintence/lubrication I need to to on the brake switch to avoid future events. It is a bit troublesome to think that such a small item can have such a dramatic impact: I guess that there are a lot of little ticking timebombs in a motorcycle - nature of the beast!

Thanks again!

[PETDOC]

Check to see if the brake light is always on. You may have something as simple as a stuck brake switch.

I'm curious as to how one un-sticks a brake switch?
While riding my '04 1150 GS back to Tennessee from Seattle, I stopped in Ft Collins, CO at 6:30 PM to pick up a spare fuel filter which had been left in a mail box. When I restarted my bike less than a minute later the brake light indicator was flashing and I had only residual braking. I used the bike to get to my motel and subsequently get dinner. Despite comments on how worthless residual brakes are on an iABS bike, I was comfortable enough with them to ride the intersate back to Tennessee. To my surprise approx 30 minutes after leaving my motel the following morning the light stopped flashing and everything was fine. I've never had a problem since. After reading this thread for the first time I think I know what happened. Which again brings me back to--How do you un-stick a brake switch?

[devauxb]

... Which again brings me back to--How do you un-stick a brake switch?

The switch is encased in a little rubber boot. In my case, I jiggled the brake lever and also manually pushed up and down on it with a screwdriver, to work it and it unstuck itself.

I plan on looking to take it off and cleaning/lubing it up (not sure how or if possible yet) or simply replacing it for a greater sense of security.

[PETDOC]

So the switch is mounted up on the handle bar near the front brake lever? My bike has partially integrated brakes (i.e., front activates rear, but rear works alone). I presume I must have another switch near the rear brake pedal.

[jingdog]

I guess that there are a lot of little ticking timebombs in a motorcycle - nature of the beast!

Thanks again!

Its amazing the lenths those Germans go to!

[JimMoore]

So you go to residual braking if you have something as simple as a stuck brake switch??!!

[kioolt]

I believe you go to residual braking if the brake switch is stuck during the initial self test when you turn the key on. If the switch sticks afterwards I don't believe you will notice any problem unless you just hear the servos running all of the time.

[PETDOC]

So you go to residual braking if you have something as simple as a stuck brake switch??!!

Jim,
With the servo that is correct. When you start the motorcycle you turn on the ignition, allow the "computer" to cycle through its program and when you see the proper sequence of dash lights flashing hit the starter. If during this start up procedure you have either of your brakes activated the servo won't engage and you will have only residual braking. There have been rare instances when I was parked on a very steep incline and had to start the bike with a brake applied. After starting I merely drove to a more level area, stopped the bike and restarted without braking so my servos would engage. If you rob banks for a living this could be problematic, but it is really no big deal.
If a brake switch were to be stuck on it would not allow the servo to engage during start up because the computer would think wrongly that a brake was applied. Your dash lights tell you that the servo is not engaged, so if you are looking at them there is no surprise. This is exactly what happened to me on one occasion in 43,000 miles. I never knew why it happened until reading this thread.

[devauxb]

Jim,
... If a brake switch were to be stuck on it would not allow the servo to engage during start up because the computer would think wrongly that a brake was applied. Your dash lights tell you that the servo is not engaged, so if you are looking at them there is no surprise. ...

Yes, that is exactly what happened to me. But evidently either I didn't look at my dash lights before I set off (with servos not working) or I misinterpreted the flashing as the 'normal' General flashing light you get that goes off after a few feet, therefore I did get a surprise the first time I grabbed my brake lever. Either way, my bad.

I have to also admit that since I have the partially integrated brakes, I rarely use by foot/brake pedal since the hand lever activates both front and rear brakes. Perhaps that contributed to the foot brake pedal micro-switch getting stuck from not enough use?