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Discussion Starter #21
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.
I am in agreement about this issue being an intermittent problem and I was also thinking it is electrical in nature. I took off the big connector on the ABS tonight and I was really hoping to find corrosion on the contacts so I would know I found the problem. But, when I pulled the connector off everything was nice and dry and I did not see any corrosion at all. I did slide the connector on and off several times so the contacts themselves would buff the surfaces. I then sprayed both sides out with contact cleaner and put it back together.

I haven't had any more sensor tests fail on the GS 911, but I am getting a little frustrated with it. Everytime I hook it up it fails to read on the autoscan until I go to the K series tab and manually do a brake code read. After that I can do the autoscan. Seems like after a few reads the tester will disconnect and I have to unhook the 911 and reboot it to do any further reading. I had cleaned the contacts of the diagnostic port to make sure they were good.

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.
@jzeiler, is this the brake bleed test you are referring to?

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I haven't been able to get any readings during this test, but after rereading your post, I think I am not squeezing the brakes hard enough during the test.
 

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That looks a bit different from what I see when I do it. I get a elongated box with a smaller inset box (target) and when I squeeze the lever there is a red bar that goes across the the long box and when the end gets to the "target" box it turns green and I have to hold it in that smaller box to get a good reading. Looks like you are using wi-fi on a phone, mine is hooked USB to the computer so the SW may be different.
 

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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.


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.
I own a different bike, an RT, but I think the ABS sensor may be the same. In any case, I have worked out a procedure to test the sensor and the wire in the field, and I made a video about it. Possibly this will help you:

 

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Discussion Starter #24
I own a different bike, an RT, but I think the ABS sensor may be the same. In any case, I have worked out a procedure to test the sensor and the wire in the field, and I made a video about it. Possibly this will help you:

I actually have already watched your video. I found it what searching for info on the problem.

I enjoyed the video and it had a lot of good info. Thanks for posting it.
 

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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.



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
Great info and education, tnx for the diagram and explanation.
Gary
 

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Discussion Starter #26
After putting the bike back together and clearing all fault codes I took it for a test ride and the fault lights immediately came on after the self test. The brakes were bled and the connector to the ABS unit was removed and cleaned with contact cleaner.

I checked it with the GS911 said the fault code was: 16769 Internal control module error-Slip duration was too long during regulation

The error codes of the sensors did not show up this time, just the internal control module failure. I am afraid this means my control unit is bad and needs replacing. Module Masters currently has the LT module fixing frozen until after January 2021.

I have a second ABS unit on a parts bike but I am skeptical about it being worth swapping over. That bike has 100k+ miles on it and has sat for a while. I don't know if it is worth the effort of taking it off of the parts bike and putting it on my bike and bleeding the lines just to see if it gives any error codes. I guess I should give it a go and try it. At the worst case scenario it fails and I just loose brake fluid and time and labor in the attempt.

I am also looking at the ABS removal but I am not sure how that would be done. Can anyone post a link to a thread explaining it all in detail?

Getting frustrated at this point....
 

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You can swap just the electronics part with that of your spare unit pretty easily, without affecting the hydraulics. The only problem is access... you may need to take the whole unit out to swap the electronics. I think you should do this. The hydraulics on the old unit might be compromised from sitting, but the electronics won't.

When you remove the fasteners on the end cap where the big ABS connector goes, you have connections from the circuit board to the motors, solenoids, and pressure sensors. Just reconnect them exactly the same way. Two of them (the sensors and I think the motors) have keyed connections but the third one can be reversed and you will get an error.
 

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Here are some shots of what you will see. The last one is to help you find the servo (red) and pump (yellow) connectors in picture 2 as you can't see them very well in this shot. Since yours is a pre facelift access to this area is very easy.

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