Brake warning lights-Stella! say it ain't so.

[Dr. Strangelove]

I am touring the Land of Enchantment, really enjoying the New Mexico scene, avoiding the weather, mostly, when on US 60, west of Magdalena this afternoon, I notice the "general" warning light go on. I stop. Restart and it goes off.

Bike is behaving fine. No issues.

Rolling along I hit the front brake lever and now the general light illuminates and the ABS warning light is flashing at 4Hz. Braking feels ok, though if I imagine it, maybe, maybe a little less braking force. Nothing like what people describe when they go to "residual." Far better than that.
I stop, restart, the boot sequence proceeds normally and all lights extinguish properly when I take off. They remain off until I tap either brake lever or brake pedal, then I get general light and 4Hz ABS flashing, until I stop and restart, only for the events to recur with the next brake application.

I get back to Socorro, and check out all lights--they are fine; fluid levels are ok, though the rear reservoir is a bit tough to see. Fuses are fine, Battery is new and has been ridden 3k miles in the past 9 days. I checked to be sure the brake light is going on with either the front lever or the rear brake pedal--that's fine.
The servo whine from the front sounds normal; but from the rear sounds a bit anemic and after I hold the rear pedal down for a while, the whine stops.

Of course it's Sunday, so Tuesday is when I can get to a shop either in ABQ or Santa Fe, or starting the process of limping home, 1300 miles? and perhaps hitting a shop in Texas on the way.
I hope this is something simple, but it probably isn't. It's probably something like the servo unit and $$$$$$$$$$.$$.

Are there two servo units on the bike, front and rear? If the rear sounds anemic, or is gone, is the front far behind?

I looked up the code for General Light ON and ABS light 4Hz and it says that:
"Gen ON, ABS flashes at 4Hz =At least one brake circuit in residual braking function mode."
http://www.largiader.com/abs/absfault.html

If that is the case, although I would prefer to have full braking power, residual braking on the rear is better to deal with than on the front.

Oh, yeah, and the damn horn bracket broke so my horn is duct taped to the R fork.
any thoughts on all this appreciated.

John

[machew01]

John, can you share a photo of the duct tape on the horn?

mac

[Xdot]

Makes me want to do a sweatmarkotomy...

[Dr. Strangelove]

That would be a "sweatmarkECTomy." Cut it out.
yeah, I am considering it, but I remember very lucidly an episode on I 59/20 outside of Birmingham when a car cut right in front of me at speed and I slammed on the brakes and thought This Is Why I Have ABS.
Maybe I was wrong, but I thought that.

The da^^n bracket broke on the horn.
Stella! is 84k old these days. But is still photogenic and a picture of her bo-bo will happen.

[Sunbeemer]

Sorry to hear of your trouble, John.
I don't know much about ABS, but understand they rely on the wheel sensors to detect skidding. Maybe it's a bad wheel sensor or damage to their wires or loosened connectors. If it isn't too difficult, it's probably worth inspecting.
Good luck and get home safely!

[sweatmark]

Hey doc - PM sent.

[towerworker]

You neglected to change the antifreeze didn't you?


When will you guys ever learn?

[Dr. Strangelove]

And I did get caught in ice on I 40 outside of Holbrook, AZ. So maybe that antifreeze thing...

Yes, Rich, I had a front sensor go bad on me on another trip.
Ordered it from Max's, it came, it was defective, and they would not take it back or credit or exchange, "because I was not a BMW shop"
Front sensor then was about $100. There is one on the rear also. They are plug and play. I didn't break it. Real good customer service...NOT

The error code was different for that though. The ABS light would boot, go out, then come back steady on even when not applying the brake.

[grwrockster]

This is why I purposefully bought a Rockster without ABS!

I think ABS is a great thing and would have had it - but heard too many scare stories about the complexity and failure rate for me to risk the repair bills. Also i tried a Rockster with ABS, and (I think combined with the OE braided brake lines) felt so grabby and sharp that I felt it needed the ABS to counteract the lack of feel, and I took an instant dislike to it.

Anyway...... My mate's R1150R got what I recall is the same symptoms with steady flashing of the warning light when we were in the Swiss Alps a year ago (right at the top of the Petite St Bernard Pass with a load of downhill hairpins to negotiate, in cloud cover and heavy rain - he wasn't happy at all!).

I hope your problem is all his turned out to be (as he'd already changed the servo out once already!)......

I know you said you checked the fluid levels (as did my friend). The problem turned out to be a slight low level in the system in the under-tank reservoir I believe (forgive me for not knowing 100%, but I don't have any of this pesky gubbins on my bike!). All i know is that he reported that the mechanic added a drop or two of fluid, and the falshing lights went away!

[omg1010]

The bike only has one ABS unit under your fuel tank which handle the front and the rear circuit. If that has gone south be prepared for big $$$

However there are quite a few things which need to be checked (ABS sensors, brake fluid level, etc). I'd see a dealer to read the error codes and hear what he has to say. If it is the central ABS unit I'd go for a used one which can be found on e-ba* or any of the salvage specialists like beemerboneyard.

In any case be happy that you have the ABS. Occasional faults can happen with any technical installations and the vast majority of BMW ABS systems work just fine. Mine for example works great since 13 years and has never let me down.

Brgds
Oliver

[Dr. Strangelove]

thanks for all the suggestions and I have to agree with Oliver. ABS to me is worth the hassle. Or maybe it's the idea or ideal of ABS that appeals.

The reality may be something else.
grwrockster wrote

I know you said you checked the fluid levels (as did my friend). The problem turned out to be a slight low level in the system in the under-tank reservoir I believe (forgive me for not knowing 100%, but I don't have any of this pesky gubbins on my bike!). All i know is that he reported that the mechanic added a drop or two of fluid, and the falshing lights went away!

OMG! I thought I was crazy or stupid or ill-equipped to address this problem, but...

I checked the fluid levels again this morning before setting out. Bike is on side stand. The level of the rear res, now better viz'd because of better light is under the min level, but technically still in normal range.
Remembering that almost anything diagnostic requires centerstand, I put her up on it. The MIN line is about 1 - 2 mm thick and the level is right at the lower edge of the min level.

There's a NAPA across the street from the Days Inn Socorro. Get some DOT 4 and a long skinny funnel--all of 7 bucks.

Man it does not take much, less than a teaspoon and the level is up into "the range."

Over 200 miles today and NO WARNING LIGHTS. I thought this has to be wrong, crazy that far less than 5cc of brake fluid would make that difference, but so far it has,

Nice to get validation, fa'sure!

I am in Santa Fe (great town, btw) and will visit Sandia BMW tomorrow am for a diagnostic check and a horn bracket ( or more duct tape)

I'll report, but the girl is behaving. Woo hoo

John

[iowabeakster]

There are 4 reservoirs in the system. Two of them are IN the ABS unit, under the gas tank. When one of those (ABS unit reservoirs) gets low, it will trigger a SPECIFIC warning light pattern. The two warning lights will flash ALTERNATELY. Typically, this will happen on turning the bike on, not when applying the brakes. It will also usually not "go away" after a restart. The "low-fluid" warning lights only apply to the levels in the ABS unit. The flashing warning lights are there because a person needs to pull the gas tank off to check those levels, so it's a convenience/safety feature.

The other two reservoirs (handlebar, and plastic cup on right side of bike) do not EVER drop in level as the pads wear. There are also NO sensors on our bikes that will trigger a warning code, even if they were low. Those reservoirs are easy enough to check.

It seems like every time somebody gets an error code (whatever warning code it may be), the common advice is to tell them to check their fluid levels. The error code you got was NOT about the fluid levels. It was about something else. There is some possibility that you could have air getting into the system (and possibly fluid leaking out). But simply adding fluid to a reservoir will not bleed the air out, and would not have rectified the error code, if air in the system caused the error code.

I wish I could be tell you exactly what the problem was, but adding fluid was NOT the reason the warning stopped. If I were to hazard a guess, I would guess low voltage in the electrical system.

I hope all that makes sense.

Also, when the servo (rear-only) stops whining after a couple seconds, while sitting stationary? That is a completely normal function. It's also normal to be quieter than the front. My bike has done that from the moment I rode it out of the dealer's parking lot, the day I bought it. There was a thread a while back. I think it was owldaddy that said his dealer even demonstrated this function to him when he got his bike new. This should not be a reason to fear you might need to replace the unit. But still the warning lights are an unanswered question.

[Dr. Strangelove]

I wish I could be tell you exactly what the problem was, but adding fluid was NOT the reason the warning stopped. If I were to hazard a guess, I would guess low voltage in the electrical system.

So, I bring her in to Sandia BMW in Santa Fe this am and they get on it (Kudos to them so far, btw).

Although the flashing sequence I saw indicated residual on at least one system--and NOT low fluid which is as you describe, the computer showed nothing for that. They came out and asked,"Is that battery new, or old, because we are picking up a history of a low voltage situation. Did that happen?"

Yes it did, new Odyssey btw, it happened about 3 weeks and over 3k miles ago. I tied XM into my zumo and had to leave the bike on for about 20 minutes to download the XM stuff. When I did that and then tried to start, she wouldn't. I put her on the trickle charger and it took about 18 hours to charge. Since then no problem w electricity or power for starting. And no unexplained flashing lights, until the other day.

So, yes that did happen, but they really didn't have an answer for the lights not recurring except for my adding a little fluid to the system.

I had a bad sidestand switch though and they said my "clutch switch" was bad also. I should be good to go by afternoon tomorrow.

puzzling behavior, could have been ghosts and gremlins.

[mikes]

I had a similar issue with warning and brake light coming on but every thing was working OK. It turns out there was some road tar stuck between the rear brake contact points on the switch. This had a few tech scratching their collective heads but found it when cleaning the bike.

Don't know if this helps.

[Boxer]

John,
If you can make it, head over to Show Low and visit Dean Lear at the Bunkhouse. He can diagnose your problem and give you a nice "motorcyclist" place to crash in the meantime.

Did you stop in and see the array just east of Pietown?

[Dr. Strangelove]

Mikes, thanks. I will check that.

And, Phil, yes I did. The dishes moved while I was there. I saw them from NM52 I think, better view than from US60. They move quickly, surprisingly so.
In the time it took to change lenses they moved over 90 degrees horizontally and about 20 degrees vertically.

And though I asked you if you had stopped in Pie Town and you didn't, neither did I. That was just at the time when the lights were acting up and my appetite for pie seemed to diminish. There are two pie places there and there were cars, but as I didn't know what was going on and had issues with braking confidence I headed back to Socorro.

Getting a new rear PR3 also, down to wear bars. I could have changed them myself before I left home, but there was sig mileage left. I figure I am paying a $60 premium by having Sandia do it rather than me, but I will have a safe tire for the 1500 miles back
I will report on my experience with the PR3s.
Heading south when I get Stella! back to lessen the impact of this cold front that has hit. Should hit the road today around 1p??

John