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Discussion Starter #1
So, I've had the flashing ABS warning sequence intermittently for the last few weeks. Since I'm basically lazy, I decided to think about it rather than just jump right in.

Symptoms:

1. Same warning light sequence as low brake fluid in rear reservoir. Fluid level is fine;checked multiple times and refilled for good measure. Checked the front as well: OK.

2. Happens during the initial ride segment of the day. Key off reset and restart (sometimes several ) clears it. Brakes still work but ABS does not kick in if lights are flashing, as I would expect...unless I have a complete pump failure.

3. Very rarely happens on subsequent ride segments, i.e. ride to lunch with warning lights, stop for lunch, restart bike...no warning lights.

4. Actually happens more often if bike has been connected to battery tender overnight than not, which seems to me to probably eliminate the battery charge as cause.

5. Warning lights start flashing on the second (!!??) stop of the day. Ride to end of alley, stop normally...no lights. Turn and proceed 2 blocks to main intersection and stop... warning lights begin immediatly after I come to a complete halt. Max alley speed...20 mph; to intersection...40 mph. Hmmm, speed related? Speedo itself is solid as a rock, so the intermittent wire break doesn't seem to be at the top of my list.

Therefore I am leaning toward a dirty sensor or bad gap. Looked in my CD brake manual which states in several places " clean ABS sensor before installation", but I can find no method or recommendation on how exactly to perform the cleaning. The sensors themselves look to be sealed, or am I missing something? And how does one clean one of these sensors correctly?

Of couse, if my diagnosis is completely off base, I am open to suggestion.:bmw:
 

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Not a K12 but

My K1100LT used to do just what you're describing,
drove me crazy, it was the battery.

Yeah I know its not a K1200LT, take it for what its worth.

Just a thought how are the brake pads?
 

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Hi Brett , I had trouble with the ABS warning lights . I put in brake fluid . That didn't help , had it on a charger that didn't help . Put in a new battery , and all's well . I put the old one in my garden tractor & it turns it over real good ,but the ABS didn't like it. Hope this helps ....Patric ...
 

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Might want to disconnect the battery for a few minutes and let the computer do a reset.

If the battery is 3 years old or more, time for a new one.

If all of that fails, ride it to the dealer and see what their computer has to say about your computer.

Mine was doing something similar, the colder it was, the worse it was, was going to be out of town for a couple of weeks, rode it to the dealer, had them do some warranty work on it, they said it had some brake fault codes stored, they cleared them and it hasn't done it since.

Let us know what you find.
 

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Brett,

I had the same experience you are having and then one day it became full time flashing and NO ABS at all. I took it to the dealer and they ran tests and said HYDRO UNIT. I rode the bike that way for nearly 4 months. You don't want to know what this bike feels like when the rear locks up. :eek: Then I read on either the old .net site or here that a battery could be the issue. I called Raffy and asked how old the battery was in Rover, when he said 4 years I went shopping. Picked up a replacement PC-680 at the local Batteries Plus+ and replaced it. Lights didn't go out. Took it back to the dealer and had them rerun the brake check and reset the lights and VIOLA, I've got ABS again.

Hans, thanks for being a rememberal. :thumb:
 

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Clean ABS sensors

Have you checked if the brake lever is sticking slightly, thereby holding on the brake light switch. I had it on my 1150RT when trying to leave work one night. Try knocking the lever away from the handlebar and see if it clears.
 

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Discussion Starter #7
Well, I replaced the battery with a PC-680 yesterday. Cleaned the sensors (w/brake cleaner) and checked the gaps (in spec). The pads are about 1/2 worn, but lots of material left.

Test drive: Started out for a friends house out in the country; no warning lights for about 5 miles till I came to a complete stop at an intersection. I had been using the brakes normally and had stopped at lights several times before the warning lights re-appeared. Pulled over into a church parking lot, reset the bike with key on/off, and resumed the ride. Tried combinations of both brakes, front lever, foot lever, whatever.
Could not get the lights to reappear. After a nice visit with my friends, fired the bike up and rode ~15 miles home with no warning lights at all. Brakes worked well and ABS kicked in as normal, both out and back. Only indication there is something wrong is the dang flashy lights! I intend to try again today before checking into what the dealer is going to hose me for to connect up to the computer to reset all the codes. I am beginning to think there's a ghost in the machine.

Thanks for all the suggestions; keep 'em coming cause this is making me nuts (not that I needed any help with THAT)!
 

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Wrencher Extraordinaire
2005 K1200LT
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One other thing to check - there are two sensors on the rear reservoir and they are in series. If one of those connectors is loose it will cause the same indication as low fluid. Worth a check.
 

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You're absolutely sure both rear reservoirs are completely full? I find mine really needs to be topped off at just below the filler neck transition to the main body of the reservoir. Not between min-max, but AT the max.

Just remember if you add fluid during brake wear, you most likely will need to siphon some off when replacing the pads.
 
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