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ABS (again...)


Rarebird13

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Rarebird13

Hi all- much searching, haven't found this one. 

 

95 R1100RS, 19k miles (5k in past 3 months!) Key on, only top ABS light lights, in motion I have constant alternating. Worked fine Thurs night, started first ride Friday. No clunk/ chirp. Was practicing quick stops (issue began BEFORE) for demoing upcoming exp.rider course, so I know ABS is definitely NOT functioning 😎

 

Have tried reset ABS2, no joy.

 

I know bike is still rideable without ABS, but would like to repair. any ideas before removing tank would be helpful- thanks!

 

-mike

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dirtrider
58 minutes ago, Rarebird13 said:

Hi all- much searching, haven't found this one. 

 

95 R1100RS, 19k miles (5k in past 3 months!) Key on, only top ABS light lights, in motion I have constant alternating. Worked fine Thurs night, started first ride Friday. No clunk/ chirp. Was practicing quick stops (issue began BEFORE) for demoing upcoming exp.rider course, so I know ABS is definitely NOT functioning 😎

 

Have tried reset ABS2, no joy.

 

I know bike is still rideable without ABS, but would like to repair. any ideas before removing tank would be helpful- thanks!

 

-mike

Afternoon -Mike

 

Best thing I can tell you from afar is to reset the ABS again, then use a GS-911, or analog voltmeter, or 12v LED to read the new stored ABS failures codes. Hopefully that will give you a direction to look in. 

 

I might not be back here for a while as I am on the trails today so unless I take a break with WiFi handy I will be off-line.   

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Rarebird13

Thanks. Need to locate my old analog voltmeter to see what I come up with.

 

Also, have new brake lines on the way, so I may just pull the ABS relay for now, dig into this all at the same time.

 

-mike

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James in OK

Is your battery FULLY charged?  I have a 2000 R1100RS and that system seems very sensitive to a battery that is not in top condition.

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Rarebird13

Brand new battery, fully charged, mod done to take battery out if before-start mix that threw ABS probs... PO had that issue, one of the first things I fixed

Thanks!

-mike

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Rarebird13

Short of removing bulbs, is there a way to disable the ABS lights on the cluster until I've had time to sort this? I've removed the relay, that seems to leave just the lower ABS light flashing

Thanks!

-mike

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Paul De

My '99 RT had an issue with  ABS faulting out intermittently and after replacing the battery and clearing the fault from the computer the problem seemed to be cured.  The fault came back about a week later, but this time it was 100% faulting out.  The real problem turned out that my front wheel pulse sensor failed and after replacing that sensor the ABS has functioned well since then.  Thankfully the bike at that time was still under warranty so the cost and work was covered by the BMW shop.

 

Because it was serviced by the dealer I have no knowledge on how to advise you about how to test the pulse sensors, but it would be worth checking before scrapping the whole ABS system.   I will take a wild guess and say if it is a failed pulse sensor and you test both the front and rear you should find one sensor showing some resistance in the hundreds to thousands of ohms and the failed one will show infinite resistance (open circuit).

 

Good luck and let us know how it goes

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dirtrider
56 minutes ago, Rarebird13 said:

Short of removing bulbs, is there a way to disable the ABS lights on the cluster until I've had time to sort this? I've removed the relay, that seems to leave just the lower ABS light flashing

Thanks!

-mike

Afternoon Mike

 

With your ABS faulting right at key-on (no lower warning light)  you definitely have a serious issue as even with failed wheel speed sensor or sensors it should boot to either both lights on, then default to alternating lights flashing  at ride-away. Or it should boot to both lights flashings if just a sensor error (like a shorted or open sensor). 

 

There is no good (easy) way to disable that other warning light as there are no fuses in the ABS  power circuits.

 

You can probably unplug the the large connector at the ABS module & that should (probably) turn the other light out. 

 

 

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Rarebird13

Thanks to both for the input! 

 

First, I have no intention of scrapping the system- quite fond of working ABS! I just don't have time to dig in at this point, and I know on this particular system non-functioning ABS does not affect standard braking- so I can keep riding for now. 

 

The lights were alternating (faulting) correctly before I pulled the relay, so no worries there. Pulling up the relay caused just the lower to flash, and i was just looking to disable lights for the time being until I can fully diagnose and repair the problem. 

 

I know pulling the tank is going to open an entirely new can of worms on a 26yr old bike, and I'd prefer not to open that can right now.

 

-mike

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Rarebird13

having considered the tap route, but hoping to use that as the last resort- hate cleaning baked on glue from and expensive piece of plexi!

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  • 1 month later...
Rarebird13

So, missed what is likely an all too obvious answer to my ABS fault. Being new to BMWs, I had no idea the tail/ license bulb would trip the fault. Local constabulary informed me of my non-functioning taillight (brake and blinkers all work) on the way home from work the other night. Changed the bulb, smacked my head, and did an ABS reset- and I now have functioning ABS again!

 

Quick reminder to any others that may have forgotten, reset after low-voltage, prestart ABS mod requires RUNNING reset.

 

Happy to have my ABS functioning again for a mere buck and a quarter- and a bit of gained wisdom!

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dirtrider
14 minutes ago, Rarebird13 said:

So, missed what is likely an all too obvious answer to my ABS fault. Being new to BMWs, I had no idea the tail/ license bulb would trip the fault. Local constabulary informed me of my non-functioning taillight (brake and blinkers all work) on the way home from work the other night. Changed the bulb, smacked my head, and did an ABS reset- and I now have functioning ABS again!

 

Quick reminder to any others that may have forgotten, reset after low-voltage, prestart ABS mod requires RUNNING reset.

 

Happy to have my ABS functioning again for a mere buck and a quarter- and a bit of gained wisdom!

Evening  Rarebird13

 

You said that you have a 95 R1100RS, on the  95 R1100RS (ABS-II) the tail light bulb has no effect on ABS operation. The tail/brake light is a separate function on the (ABS-II) motorcycles. 

 

Now on the later (I-ABS) wizzy brake systems the brake/tail light  bulb does have an effect on that ABS dash lights (doesn't stop the ABS from functioning though).

 

You will probably find that the RESET is what got your ABS working not the tail light bulb. 

 

 

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Rarebird13

Interesting- this claims otherwise (and it worked): 

http://largiader.com/abs/absfault.html

 

ABS2

ABS2 was used on K1100 from 1994 onwards, R1100RS/RT/GS/R, and early R1100S, R1200C, R1150GS, and K12 models.* The K11 ABS2 uses the same two warning lights as ABS1: the ABS light and the bulb monitor light. On Oilheads and K12s, it has two distinct lights of its own. At key-on, the two lights will flash together and continue to do so until the self-test is complete (which doesn't happen until you start to ride away), at which time they extinguish. If the self-test fails, they will begin to flash alternately. The exact moment when the fault happens will help you know what caused it: if it happens before you start the engine it is an item that is tested at power-up. If it fails when you start the engine, it is almost certainly low battery voltage. And if it fails when you ride away, it's probably a modulator or a wheel speed sensor.

Sometimes ABS2 will fault without showing a fault code that you can read without the diagnostic computer.

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dirtrider
20 minutes ago, Rarebird13 said:

Interesting- this claims otherwise (and it worked): 

http://largiader.com/abs/absfault.html

 

ABS2

ABS2 was used on K1100 from 1994 onwards, R1100RS/RT/GS/R, and early R1100S, R1200C, R1150GS, and K12 models.* The K11 ABS2 uses the same two warning lights as ABS1: the ABS light and the bulb monitor light. On Oilheads and K12s, it has two distinct lights of its own. At key-on, the two lights will flash together and continue to do so until the self-test is complete (which doesn't happen until you start to ride away), at which time they extinguish. If the self-test fails, they will begin to flash alternately. The exact moment when the fault happens will help you know what caused it: if it happens before you start the engine it is an item that is tested at power-up. If it fails when you start the engine, it is almost certainly low battery voltage. And if it fails when you ride away, it's probably a modulator or a wheel speed sensor.

Sometimes ABS2 will fault without showing a fault code that you can read without the diagnostic computer.

Evening  Rarebird13

 

Interesting, I don't see where it says anything about the tail/brake lights or light monitoring causing the ABS system to fail work on the 1100 RS.

 

No way would BMW set the system up to FAIL/disable the ABS with just  a simple tail light out. (doesn't pass the common sense test).

 

  

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Rarebird13

I guess I misread  "The K11 ABS2 uses the same two warning lights as ABS1: the ABS light and the bulb monitor light." as applying to the R1100RS as well.

 

Whatever the reason, it worked- and I'll still take a "mystery win" as a win and roll with it!

 

Also, not to tick off the hardcore BMW fans, but I've worked on nearly every brand of motorcycle over the past 40 years - and BMW is no more immune from items that don't pass the "common sense test" than any other brand (can we talk about individual turn signal switches cancelled by one weirdly placed cancel switch, for instance?)- goofy things that make little sense can show up on any brand (and I really like my R1100RS anyway!)

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