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Recently I asked about (and got some great advice on) bleeding the abs system on my 1150 RT. All went well and the system worked great for about a week, then the brake failure light (top one on the panel) went to the fast flash and the brakes went to full manual mode. I nursed the bike home and started reading posts here and on other forums and was pretty much convinced I was in for the $2,500 dollar replacement bill. I found one post where someone said you should check the contacts on the fuses and relays, clean them thoroughly and replace. Much to my delight this fixed the problem, well at least for a day. Riding in to work this morning everything was fine, at lunch I went out and when I started the bike after eating the light went into fast flash mode again. The brake light (on the rear fender, not the instrument panel) is on continuosly and the pump is not whining. The brakes require considerably less effort than when the first failure happened (or maybe I just got used to it after it scared me to death), albeit considerably more than with full system functionality. The battery is new this season and fully charged, I removed the cables and cleaned them and made sure there was good connectivity to the battery, I cleaned the spades on every fuse and relay, especially the one that controls the abs circuits. I verified that all 4 reservoirs are full, and bled each circuit again. I'm out of ideas and starting to wonder if my infactuation with BMW was a mistake. I've admired these bikes forever, but I'm beginning to wonder. I'm a far cry from wealthy, and my buddy who rides a Japanese bike just smiles and says that's what I get for buying a German bike. Any ideas out there on what I might be up against? I've got a ride out to Topeka scheduled for the end of the month to see the AMA superbike races and I'm thinking if I'm going to remove the abs system I need to get going pretty quick. Any advice would be appreciated. Thanks.
keith

Keith,

if you have an ABS problem and at the same time your tail brakelight is on continuously and your fuelpump is not whining (not working) this indicates that you have some kind of electric/electronic bug (because the fuel pump is on a different connector/wiring than the ABS). It could either be a motronic problem or some kind of wiring/connector problem. That is really hard to find out and almost impossible to give any kind of recommendation from the distance. My suggestion would be to go see the dealer and let him diagnose the problem and when it comes to repairing/buying parts you could always do this on your own ...

Kind regards from Germany
Oliver

omg1010 wrote:Keith,

if you have an ABS problem and at the same time your tail brakelight is on continuously and your fuelpump is not whining (not working) this indicates that you have some kind of electric/electronic bug (because the fuel pump is on a different connector/wiring than the ABS). It could either be a motronic problem or some kind of wiring/connector problem. That is really hard to find out and almost impossible to give any kind of recommendation from the distance. My suggestion would be to go see the dealer and let him diagnose the problem and when it comes to repairing/buying parts you could always do this on your own ...

Kind regards from Germany
Oliver

Pretty sure he means the servo pump since no mention was made of the fuel pump...

combustor777 wrote:

omg1010 wrote:Keith,

if you have an ABS problem and at the same time your tail brakelight is on continuously and your fuelpump is not whining (not working) this indicates that you have some kind of electric/electronic bug (because the fuel pump is on a different connector/wiring than the ABS). It could either be a motronic problem or some kind of wiring/connector problem. That is really hard to find out and almost impossible to give any kind of recommendation from the distance. My suggestion would be to go see the dealer and let him diagnose the problem and when it comes to repairing/buying parts you could always do this on your own ...

Kind regards from Germany
Oliver

Pretty sure he means the servo pump since no mention was made of the fuel pump...

Naah... He's using the fuel pump to check if there's a general problem with the electrics.

NoRRmad wrote:

combustor777 wrote:

omg1010 wrote:Keith,

if you have an ABS problem and at the same time your tail brakelight is on continuously and your fuelpump is not whining (not working) this indicates that you have some kind of electric/electronic bug (because the fuel pump is on a different connector/wiring than the ABS). It could either be a motronic problem or some kind of wiring/connector problem. That is really hard to find out and almost impossible to give any kind of recommendation from the distance. My suggestion would be to go see the dealer and let him diagnose the problem and when it comes to repairing/buying parts you could always do this on your own ...

Kind regards from Germany
Oliver

Pretty sure he means the servo pump since no mention was made of the fuel pump...

Naah... He's using the fuel pump to check if there's a general problem with the electrics.

He's obviously riding the bike with failed ABS (and impossible with no fuel pump), and besides that makes no mention of a fuel pump failure. The poster (omg1010)mistakenly saw "pump" and thought "fuel pump" instead of "servo pump" which is what the OP is referring to. I'm merely pointing this out to avert a misdiagnosis and chasing a problem that isn't there.

Good point.

Sorry folks I apparently got it wrong. Yes it may off course be the servo pump. But any failure on the servo pump is hard to diagnose unless one has the testing equipment the dealers have or by any chance a replacement unit for testing purposes ... Sorry but I don't have any good recommendation other than going to the dealer and get the thing checked.

Kind regards
Oliver

Does the fast flashing light begin at "key-on" (the intitial self-diagnosis) or after you start riding away (the wheel sensor test)?

The very first thing I would check is the switch at the food pedal. (This was the answer to the last person who had ABS trouble) Make sure that the switch is "clicking" and the contacts are CLEAN. There is a disconnect for that switch that is zip-tied to the frame near the fuse box. Just follow the wire up (this is assuming the RT is the same as my R). You should be able to verify the electrical current and test the switch with a multi-meter. The normal "resting" state of the switch is closed (electrical current flowing). When you depress the pedal...the circuit opens (stops electical current) triggering a relay to light the brake light and operate the servo pump.

The second thing I would check is the front brake lever. Make sure that the lever fully returns to its resting position. If some old gunk is in the works...it might provide enough resistance to prohibit the free movement of the lever and keep it from returning to its resting position. There is also an electrical switch inside the handle bar unit. (same deal as the switch at the foot pedal...clean...click...test...).

Hey guys, thanks for all of the replies. The fast flash does start immediately upon turning the key on, it never goes to the slow flash cycle. I'm working late tonight as we've got a server acting up at work so I probably won't be able to check anything tonight. Just to clear up the confusion I seem to have caused, I am referring to the servo, not the fuel pump. I'll verify that both brake light switches are opening when I get a chance (I'm sure they have a good reason to go through a relay and break a circuit in order to supply power to a light but it sure seems like a deliberate attempt to complicate what could be a very straight forward system). The nearest BMW dealer is down in Santa Fe, a 4 hour drive from here, so I won't be taking it to the dealer unless I have no other options. Besides that I've been doing all my own maintenance on my bikes since 1968 and if I have to give that up just to own a Beemer I'll go back to Japanese bikes. Again, all of your comments are appreciated, this forum is gold mine of good information.
keith

The very first thing I would check is the switch at the food pedal.

I was in need of a double cheeseburger at the time I wrote that...that should have said "foot pedal".

Now we are really onto something. Iowa is right I think. The exact symptom can be replicated by holding the brake when turning key-on, or grabbing brake before self test completes. It is almost certainly the hand or foot brake switch, or damaged wire thereof.

kjk wrote:I'll verify that both brake light switches are opening when I get a chance (I'm sure they have a good reason to go through a relay and break a circuit in order to supply power to a light but it sure seems like a deliberate attempt to complicate what could be a very straight forward system).

The best reason I can come up with is that if the switch was momentary-on instead of momentary-off, during the start-up check the bike wouldn't be able to determine is there was a wiring fault with the brake switch, and couldn't alert you to the issue. You might be riding for quite awhile (depending on how often you do a bulb check) before noticing that the rear brake doesn't light the lamp.

Matt Pie,

Yep, in order to test the circuits... the circuits must be closed.

I had exactly the same problem on my Rockster today and tracked it down to a faulty foot brake switch.

The previous owner had fitted a Wunderlich footrest lowering kit, however it hadn't taken me long to discover that the previously unblemished 'hero blobs' were decking out just about everywhere, so decided to put footrests back to standard.

Fairly straight forward job, took about twenty minutes. Finished up job, put bike back in the garage. Two days later thought I'd ride into work.

Ignition on, bike fired up, brake warning light flashing rapidly. No brake servo noise. Loud and rapid clicking noise under the seat. Rode the bike a few feet, light didn't extinguish. Relay under seat still clicking fast. Brkaes alarmingly poor!

Noticed that the brake light had come on with the ignition even though neither hand nor foot brake was being operated. Examined the footbrake assembly, as that was the only thing that I might have buggered up. Pulled and pushed the foot brake lever, and lo and behold, when pulled up, brake light went out and clicking noise went into a slower mode. Brake warning light still illuminated on dash, now flashing slowly.

Examined the spring 'blade that is operated by the adjuster bolt on the brake lever itself, and which in turn operates the brake light micro switch. I could see it was slightly mishapen, and wasn't depressing the microswitch fully when 'at rest'. I tweaked it a bit to reshape it and bingo, now working properly.

Ignition off, back on again and bike goes into 'brake check' mode, servo primes, brake light not lit, dash warning light flashing, relay underseat still clicking but slowly, in time with dash warning light.

Fire her up, servo now operates with either brake lever and dash light goes out as soon as you've moved a few feet, and realy under seat stops clicking.

Problem solved. I think!!

Well I should have replied sooner but I've been pretty frustrated with this thing. The problem did turn out to be a sticky switch in the front brake lever. I got that sorted out without much pain, rode the bike into work the next day with a grin on my face but then on the way I home I pulled up to a stop light and caught a whiff of something that smelled like brake fluid burning. It has to be a coincidence, but the line that runs from the fitting on the frame down the fork leg and then branches off to both front calipers sprung a leak in the rubber section near the top and was shooting out brake fluid at a very high pressure when the front brake was applied. I'm waiting for that section of brake line to come in now, a $125 part in the skewed world of BMW parts pricing. I seem to developing a love hate relationship with this bike, love it when it's running and hate it when it's not. Thanks again to all of you for the helpful suggestions and comments, cross your fingers and hopefully this will be the end of my brake system issues.
keith

Friggin unbelievable...my fingers are crossed...that this is the last of your problems.

The OE brake lines are indeed a mess. Makes a brake system bleed a pain. Even with the ABS in place you might consider simplifying the connection to front calipers when moving to aftermarket brake lines. Change from the old rubber to stainless shrouded lines is worth the expense.