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Discussion Starter #1
I know this has been discussed a lot on the forum and I have read a crap ton of the threads posted here but none of them seemed to be exactly what my symptoms presented as so I decided I would add mine to the ever growing list of ABS posts.

History -
I have only owned my LT for 6 months so I don't know the long term back story....
The Spiegler ( correct spelling? ) brake lines were dealer installed by the previous owner....
A new battery was installed due to weak starting....
A couple of months after buying the bike I had the ABS warning light and the general warning light come on after I hit a pretty bad pothole. I pulled over at a parking lot and turned off the bike to inspect for damage. I didn't find any so I started the bike back up and the warning lights were no longer flashing. Several weeks went by before the flashing dash lights came back. I can't recall what caused them to come back, but they also went away after restarting the bike and allowing the bike to do its self test.
About two weeks ago the warning lights began to come back much more frequently and at the beginning, allowing the self test after turning on the ignition to reset the lights would work, but in the last week the lights on the dash would immediately come back.
The brakes seemed to work properly when the warning lights would come on but I never pushed the brakes to the lock up point to test the ABS during these episodes.

One thing to note is I would always get the warning lights when the brakes were not being applied, only when the wheels were spinning. This made me think it might be a sensor issue. Applying the brakes, even vigorously, would not set off the warning lights.

The last time I had an issue with the brakes was the last time I rode the bike.

I had checked the sensor gap and made sure the gaps were within the specs, topped off the reservoirs with brake fluid, inspected the brake pads and then I went to a test ride thinking the fluid level was the culprit since it was a tad low. As soon as I pulled off the warning lights came on but I continued my trip to the store. Coming back I was going about 40 mph and was coming up to a traffic light. There were about 10 cars in front of me and I began slowing down and had plenty of room to make the stop. I had slowed to about 25 mph and suddenly the deceleration sensation of stopping was gone and I had no braking power whatsoever. It felt like I had hit a sheet of ice and I was sliding. I knew this was not true since it was 60 degrees and I was able to maneuver the bike. Fortunately there was no oncoming traffic so I swerved into the oncoming lane to avoid eating the hatchback in front of me. I passed about 2 or 3 cars while in the oncoming lane before I could get adequate braking control back. The sensation when the brakes failed was like I had simply released the brake lever and had quit trying to stop. When It failed I released the brake lever a couple of times to try and get the brakes to re engage and they did after a few squeezes. After that one issue of no brakes it did not happen again.

I limped back home and parked the bike until I could resolve this issue.

I again checked all fluid levels, sensor gaps, checked for bad wires on the sensor leads, brake pads, battery voltage and found nothing. I checked the sensors for resistance and could not get reliable readings. I checked both front and rear sensors and could not get readings.

I decided to bite the bullet and order a GS911 code reader and see what codes were present.
I got the 911 in and set it up and tried using it. It was frustrating at first since I did not know what I was doing and couldn't get a connection to my bike for the first several attempts. After finally figuring out how to connect to my bike I was able to connect and pull the codes. I got codes for a defective warning lamp and rear ABS sensor error. I had a spare sensor from a parts bike and tried it and came up with a sensor error also. I began to think there may be a bad wire between the sensor plug and the ABS control unit but I could not find anything pointing to a bad wire. The next time I checked codes with my 911 everything checked out ok with the exact same sensors. I have checked multiple times and sometimes get errors and sometimes all is good.
I am beginning to think there is a bad connection somewhere that I cant see it. I have even went so far to strip the outer insulation of the sensor wire thinking the bad connection was there but I didn't find anything.

I am not sure if these symptoms indicate a failing ABS control unit or not, but I am getting to the point of frustration. I am quite confident it is an electrical problem since every time I have gotten the warning lights I was not actually using the brakes, only rolling.

Any help or guidance would be appreciated.
 

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Discussion Starter #2
One other thing I forgot to add, I have ordered the brake bleed funnel and will bleed the brakes when I get it to ensure there are not bubbles in the lines. I don't really think there is any air but I want to eliminate that possibility.
 

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The warning light pattern you get is important information. There are two lights - General Warning and ABS - and you get fast or slow (or no) flashes on each. The combo you see has a specific meaning.

Also, now that you have the GS-911 you should do a brake bleed test. You should not be without brakes if the power assist fails. Residual braking is much weaker than assisted braking, but it will still stop the bike.

I am assuming you have Integral ABS based on your desire to buy the funnel tool. Correct?
 

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Discussion Starter #4
The warning light pattern you get is important information. There are two lights - General Warning and ABS - and you get fast or slow (or no) flashes on each. The combo you see has a specific meaning.

Also, now that you have the GS-911 you should do a brake bleed test. You should not be without brakes if the power assist fails. Residual braking is much weaker than assisted braking, but it will still stop the bike.

I am assuming you have Integral ABS based on your desire to buy the funnel tool. Correct?
The warning lights are the normal startup flashes, 4 hertz during the self test then it drops to the 1 hertz and remains at 1 hertz.

I do plan on the bleed test once I get the funnel, should be in tomorrow.

Yes the brake system is the integral system.
 

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2005 K1200LT
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The bleed test can be performed at any time. You really have to work at it as you squeeze the lever to keep the display in the green , centered in the marks. I usually have to use two hands for the front test and lots of foot pressure for the rear. If it passes you have no air in the system.

The symptoms you described do not relate to air in the system. Sounds like an intermittent so I would look at the main big connector on the ABS and look for corrosion there. Normally a wig wag of the lights at 1 hz is an indication of low fluid in the rear dual reservoir, but that usually does not lead to a loss of brake power.

Let us know what you find on the bleed test.
 

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Scary. On that brake failure when you were coming up to the stop light, did the front brake lever move in and out just like normal, did it feel normal, or did it feel hard like there was a block of wood between the grip and the lever?

And do you normally use both fronts and back when approaching a light, or just the fronts?
 

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I have to agree with jzeiler. It does sound like a bad plug connection.
I used to get some funny things happening on my bike. I would occasionally have the speedo fail and sit on zero. Some time ago I decided to pull the front cowling apart and unplug the large plugs on the back of my instrument cluster. I cleaned the pins with contact cleaner and plugged it all back up. I never saw that problem again . The LT has more than it's fair share of plugs and connections and many of them at some point will be exposed to some degree of potential moisture ingress. Another thing that happened was I replaced my EHCS unit that had been missing since I bought the bike. I couldn't get it to work until I had traced the circuit. In doing so I unplugged those connection, tested them and plugged them back together. I never found a problem but after jacking all the connection it worked perfectly.
 

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Discussion Starter #8
Scary. On that brake failure when you were coming up to the stop light, did the front brake lever move in and out just like normal, did it feel normal, or did it feel hard like there was a block of wood between the grip and the lever?

And do you normally use both fronts and back when approaching a light, or just the fronts?
The brake lever seemed to operate just fine, nothing to indicate the input from my hand was not getting to the ABS unit at all.

I normally use the back brakes for slowing to a crawl and then transition to the front brakes for the last few feet of the stop. Since I was having brake issues though I was using the front brake just to have a better feedback through my hand instead of my foot. At the point of the brake failure I am not exactly sure what I did since it happened so fast. I believe I had started using the front brake to slow and finally stop, but when the failure hit I think I got on the back break as well and had no effect. I am not sure though so don't consider that in trying to figure out my problem, the only thing I really remember was a Volkswagen logo getting much closer than I would have liked at the speed I was going ;).
 

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2005 K1200LT
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The brake lever seemed to operate just fine, nothing to indicate the input from my hand was not getting to the ABS unit at all.
That is normal as the fluid really does not go anywhere since the input is fully isolated from the servo output.

I normally use the back brakes for slowing to a crawl and then transition to the front brakes for the last few feet of the stop.
You cannot use just the back brakes (except for very light trail braking) as they are fully linked and you will get both front and rear regardless of the input.

This diagram shows the basic function of the system.

171732
 

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Discussion Starter #10
That is normal as the fluid really does not go anywhere since the input is fully isolated from the servo output.



You cannot use just the back brakes (except for very light trail braking) as they are fully linked and you will get both front and rear regardless of the input.

This diagram shows the basic function of the system.

View attachment 171732
I agree with you on the linked brakes, but I am trying to train myself to use the back brakes to slow myself and then the front brakes for the final few feet for the times that I am riding something other than my K bike. Just a good habit to learn I think.
 

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Yeah good practice. I like the system on my 09 K1300GT as it is linked from the front to the back but I can use just rear braking without getting fronts in.
 

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That is normal as the fluid really does not go anywhere since the input is fully isolated from the servo output.
Well, in residual braking the input is not fully isolated; that's the whole thing of how residual braking works. Yes the fluids are separate, and during normal braking operation you can say they are isolated, but in this case we are talking about so-called brake failure so you need to describe it in terms of residual braking. And in that case the hand lever is applying fluid pressure on the output side of the servo.

If the brakes are not bled properly you will have no residual braking, and it is the "total loss of braking" that I was responding to. Air in the system may not contribute to the ABS fault he is experiencing, but it is the #1 cause of loss of braking.

Residual braking can be tested in a parking lot or other controlled situation of your choice, but the bleed test is the definitive answer.
 

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Residual braking does not pass fluid to the output. Look at the diagram I provided the piston pushes the rod into the check ball and then moves fluid on the other side to accomplish residual braking. The fluid never mixes.
 

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Not sure if you're talking to me. I know (and said) fluid doesn't mix. I said the input is not decoupled from the output. If he truly has "no brakes" he needs to fix that independently of his ABS fault.
 

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Discussion Starter #15
Just to clarify, the "no brakes" sensation I had only lasted a few seconds, after stopping, the brakes came back and it did not happen again all the way to the house.
I know it still could have air in the lines but I feel my brake failure was caused by and electrical issue. Mechanical failures rarely fix themselves, an open circuit or short can temporarily fix itself. Right now the brakes work, just the lights are popping on after the self test.
 

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There are two things going on with your "no brakes" scenario. One is that there's a fault in the system that's causing the error code and apparently caused your ABS unit to shut down the servo assist in the incident you describe. I'm not really talking about that one; you'll probably figure it out. If the worst code you have is a sensor fault, it's probably not going to be that bad.

The second one, that I AM talking about, is that there should be no such thing as the "I had hit a sheet of ice and I was sliding" feeling even when the servo shuts down. If the brakes are bled properly, you should have residual brakes which are definitely a lot weaker but not sliding on ice weaker. It is really, really important for every iABS bike to have properly bled circuits and pass the bleed test. With experience you can feel it in the hand lever which may be why jzeiler asked about the lever feel. Along those same lines I was in touch some years ago with a guy who told of a situation he could reproduce where the lever went solid and he had no brakes. Unfortunately I just didn't have the bandwidth at the time to investigate it but I think I know what was going on.

So, while the typical rider may not - with good reason - care beyond "I lost my brakes," the people who can help you can probably glean a lot from details like how the lever felt, etc. If it came back to the grip, if it was solid, if it felt mushy but then firmed up, etc. Squeeze the brake lever really hard with the key off and report back. Normally it'll get firmer and then you'll feel and hear a click, and after that it is a LOT firmer as you move the residual piston and actually start to apply the brakes. If the control circuit has air you may never feel the click. If the wheel circuit has air you may feel the click but won't get braking pressure.

Sorry to harp on this but it's important. All riders with iABS should ensure that residual braking is effective on their bikes.
 

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I agree with you on the linked brakes, but I am trying to train myself to use the back brakes to slow myself and then the front brakes for the final few feet for the times that I am riding something other than my K bike. Just a good habit to learn I think.
As a Total Control instructor (well, former one since PA DOT shut down their program due to covid), I will argue this is a terrible practice. You should always practice stopping using both brakes, but particularly should focus on using the front brake as it provides 90% or more of your braking force. I stop this way all of the time as I want to have the muscle memory in place to make effective emergency stops. Under stress, you tend to subconsciously revert to how you have done things most often. In an emergency stop, the rear brake is only effective for the first few milliseconds after brake application. As the deceleration ramps up, the weight shift from rear to front makes the rear brake quite ineffective very quickly and makes the front brake increasingly effective.

We teach riders to apply both brakes quickly and firmly (not a sharp jerking motion, but a fast and smooth squeeze/press) and then slowly release pressure on the rear to avoid skidding as the weight transfers forward and continue to squeeze the front brake harder as the weight transfers to the front tire. Even without ABS, on most bikes it takes a pretty healthy squeeze on the front brake to lock the wheel on a dry surface. Unless you are doing very specialized riding such as off-road, trials, stunt riding or making a very slow U-turn, there is no reason to not apply the brakes simultaneously with primary attention given to the front brake.
 

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I had the same thing happen a couple of days ago. Scary, but I was able to stop.Totally agree with making sure residual braking is effective. Both flashing lights are on. Topped off both reservoirs. Still flashing. I can hear servos kick-in when applying either brake. However I started smelling and saw smoke coming out from the ABS unit area. Parked and trying to figure out what to do next... Smoking ABS? It is a 2005 K1200 with 98K miles.
 

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Discussion Starter #19
@Voyager I agree with part of your premise on braking, and I will concede you as an instructor know more than I do when it comes to riding. I also know "Under stress, you tend to subconsciously revert to how you have done things most often." statement is true and this is one of the reasons I want to train myself against snatching the front break first. My personal concern with grabbing the front break first is the fact that if you hit loose material such as gravel, sand, ice ect. and you grab the front break in that panic situation, you most likely will lose the front wheel out from under you ( with non linked brakes of course ). With linked breaks this is not really an issue since they are both being applied. I just want that habit in case I am riding a non linked bike.
I agree that 90% of braking force comes from the front wheel due to the weight shift you described but that wheel wont stop you for nothing if it is laying sideways on the pavement next to you once you have it slide out from under you.

I grew up on dirt bikes which I know are very different than street bikes but they both have two wheels. One thing I learned riding dirt bikes is you can still steer somewhat and sometimes recover if the back wheel slides out from under you, but if the front goes out from under you its time to tuck and roll.

I can also provide riding instructors that teach to practice applying the back brake to slow yourself and then finish up with the front brake as you put your feet down to stop. I am not talking about a sudden stop situation, I know I will need that braking force coming from the front tire to get stopped in that situation.

Just my 2 cents worth....
 

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@Voyager I agree with part of your premise on braking, and I will concede you as an instructor know more than I do when it comes to riding. I also know "Under stress, you tend to subconsciously revert to how you have done things most often." statement is true and this is one of the reasons I want to train myself against snatching the front break first. My personal concern with grabbing the front break first is the fact that if you hit loose material such as gravel, sand, ice ect. and you grab the front break in that panic situation, you most likely will lose the front wheel out from under you ( with non linked brakes of course ). With linked breaks this is not really an issue since they are both being applied. I just want that habit in case I am riding a non linked bike.
I agree that 90% of braking force comes from the front wheel due to the weight shift you described but that wheel wont stop you for nothing if it is laying sideways on the pavement next to you once you have it slide out from under you.

I grew up on dirt bikes which I know are very different than street bikes but they both have two wheels. One thing I learned riding dirt bikes is you can still steer somewhat and sometimes recover if the back wheel slides out from under you, but if the front goes out from under you its time to tuck and roll.

I can also provide riding instructors that teach to practice applying the back brake to slow yourself and then finish up with the front brake as you put your feet down to stop. I am not talking about a sudden stop situation, I know I will need that braking force coming from the front tire to get stopped in that situation.

Just my 2 cents worth....
When riding on the street, the odds of being on sand or gravel at the time you need to make an emergency stop are slim to none. One should learn techniques that apply most of the time, not that only apply in rare circumstances.

I learned to ride in the dirt also as I started riding at age 10 and rode off-road for 6 years before I could get my street license. There are a LOT of techniques that apply in the dirt, but do NOT apply on the street. That is why I excluded off-road in my first comment. Not using the front brake hard is one of those and putting your foot down at the start of a slide is another.

Many years ago when I owned my Voyager XII, I was riding to work one morning after a very light rain. I had to ride through a construction zone where land movers had been crossing the road carrying dirt with a heavy clay content. There was a 30 foot or so wide swath across the road covered with a thin laying of smooth and very hard packed (and slightly wet) clay. I thought I was holding steady throttle as I crossed at about 25 MPH, but the rear tire was still getting enough torque that it began to spin enough to allow the rear of the bike to start down the crown of the road towards the berm. As a long-time dirt rider and fairly new street rider, I did what I had always done and put my left foot down. This was before I joined the ATGATT world and I was wearing sneakers. By the time my foot got to the ground, I was clearing the clay and getting back to the pavement. My sneaker locked up quickly with the pavement, even though it was wet, and my leg was flung backwards nearly up over my shoulder. I am still not sure how I saved the bike, but apparently the impact was enough to keep the bike from going down and after a short and mild tank slapper, I was on my way again. I was in my early 20s at the time and didn’t feel all that bad at first, other than feeling foolish for doing that, but the next day I could hardly walk. I think I had stretched every muscle and ligament from my foot to my shoulder!

I would be curious to know which instructors you know who teach the technique you propose. I am not aware of a single instructor or training organization that recommends anything even close to what you suggest. The closest is Motorman, but that is for a very specific circumstance and I am pretty sure even he recommends using both brakes in anything other than very low speed tight turns.
 
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