Brake warning light and ! lights flashing rapidly

Hello fellow lovers of the best motorcycles in the World! I am a fairly novice enthusiast and have a 2004 r1150 rockster that I recently purchased (second one I've had).
This one has abs and I have run into a hiccup. I took it out the other day and almost ran into a car as my servo brakes stopped functioning. I still have brakes I just have to squeeze very hard. Both the abs and lights and the ! light are on. The abs flashes rapidly, pauses after 3 lights, and then continues to flash rapidly. I have replaced the relay and done a visual inspection and can't seem to find any obvious issues. Where should I start the diagnostics? Any help is greatly appreciated.

Welcome to the forum! Sorry you're having issues...and glad you have a strong right hand!!

Check out some of the threads in the Similar Threads pane at the bottom of the screen. This one has some related info:

https://forums.bmwmoa.org/showthread.php?92596-brake-failure-and-general-warning-light-flashing

If you have access to a GS-911 the error codes revealed there would be useful. An ‘04 bike would have iABS; you can see the faults indicated by the flashing lights at http://www.largiader.com/abs/absfault.html in the iABS section.

Best,
DeVern

Most likely your reservoirs are low on the servo unit. You should probably pull the tank and check the reservoirs. Going to that much work it would most likely be wise to service the system by replacing all the fluid by bleeding all 4 circuits. It's not hard but you'll need to follow a repair manual step by step. Also it would probably be a good idea to replace pads and brake lines to the SS Braded type.

Good luck and be patient.

Welcome to the site.
Check the easy stuff first.
Check all three brake reservoir chambers. It easy to not notice the back reservoir has two chambers.
You might need a flashlight to see the fluid level in both rear chambers.
Also check the one on the right side handlebars.

Make sure your battery is fully charged. A weak battery can trigger the lights.

Thank you all for the help so far. I just ordered a gs-911 since I’m sticking with the BMW family and will let you know what I find out. The error code appears to be (based on flashing light) Gen ON, ABS flashes at 4Hz =At least one brake circuit in residual braking function mode. the brake servo does not engage when I engage the front brake first. Once I hit the rear brake I hear them and then they engage on front as well. Don’t know if that helps at all. The reservoirs appear full to me.

As Lee said, check the easy stuff first. I’d suggest starting with the microswitches at the handlebar and brake pedal to make sure they are functioning correctly. If one of those picks up some debris or gets out of adjustment it can flag a failure on the iABS test at startup, and that can throw the error you are seeing. Based on your description I’d look really closely at the handlebar microswitch.

Best,
DeVern

You pulled the tank????

Just got the gs-911. Here’s what I’m seeing:
What do put guys think?

Have you still got the original rubber brake lines on the bike?

Complete fluid change with proper order of bleeding should take care of that.

BC1100S said:

Have you still got the original rubber brake lines on the bike?

Click to expand...

I believe they are. I will check later today. A bmw dealer did a complete fluid change less than 400 miles ago along with several other repairs. I’ve only had it for about three months and maybe 50 miles.

The first time this evidenced, did the self-check complete successfully before starting the ride? Did you have functioning brakes at the beginning of that ride and they stopped working during the ride, or did you experience “residual braking” the first time brakes were applied?

Digging deeper into the codes on the GS-911 should reveal mileages or dates when those codes were set, since some could have been there a while. If this were my bike, the first thing I’d do after the research is clear the codes then power on the bike and let the self-check complete before putting the bike in gear and carefully riding it a very short distance (end of block and back) so the iABS system is fully up and both brakes have been engaged. Then pull codes again so you have a current reading. The most concerning is the 17419 on the pump.

IMHO, things to check/do:

With the bike on centerstand you should be hearing the pump briefly energize when the key is turned on and self-check is running, then hear the pump engage continuously when either front or rear brake is engaged.

Fluid levels in F/R reservoirs.

Condition/alignment/proper release of brake switches at handlebar and rear brake pedal. They are critical to triggering the boost pumps.

Inspect OEM brake lines—they can collapse internally and hold pressure in the brake system on either side of the blockage. A bike this vintage is due or overdue to have OEM lines replaced with SS lines from Spiegler or Galfer

Correct flush and bleeding of the brake system. The procedure and necessary equipment can be found online, but it’s a job many prefer to leave to the dealer. If you have a failed boost pump it will evidence during the flush & bleed.

One last question—are all the lights (TS, tail, brake, 4-way) functioning correctly? A failed TS relay on these bikes can mess with the ABS system. DAMHIKT…

Good luck and keep us posted,
DeVern

As jrogers suggested, you need to pull the tank to verify brake fluid level in the ABS controller.

The front master cylinder and rear master cylinder levels are easily checked, but you need to pull the tank to see the level in the iABS controller.

I would question the dealer about it then. If they did do it 50 miles ago then they didn't do something right, causing your problem.
This is what the unit under the tank looks like, caps with the Hex are the reservoirs you need to check.

jrogers said:

I would question the dealer about it then. If they did do it 50 miles ago then they didn't do something right, causing your problem.
This is what the unit under the tank looks like, caps with the Hex are the reservoirs you need to check.
View attachment 86429

Click to expand...

Those reservoirs look fine and the brake lines have been upgraded. The dealer it was at is a few hundred miles away so not much of an option and it was the previous owner that had it there. I’ll play around with the gs-911 to find the additional info then put clear and go for a test drive to see what comes back up. Thank you all for the continued help.

Test drive complete. The only fault code showing now is 17182. Going to take apart the front brakes to check everything out but honestly not sure what all to look for. As mentioned the bmw service tech bled the brakes but I can give it a shot too. I will also be looking at the pads. Servo brakes seemed to work in the rear (could hear and engaged well) but not in the front.

mcraffeldt said:

Test drive complete. The only fault code showing now is 17182. Going to take apart the front brakes to check everything out but honestly not sure what all to look for. As mentioned the bmw service tech bled the brakes but I can give it a shot too. I will also be looking at the pads. Servo brakes seemed to work in the rear (could hear and engaged well) but not in the front.

Click to expand...

If you haven't bled this type of brake system before, be sure to have the proper tools and funnels to do the job - it isn't at all like bleeding a standard brake system. In order to diagnose quickly and easily, follow the instructions of GTRider in Post #13.

Sorry for asking twice, but did you get a good look at both chambers of the back reservoir?
The inside chamber is hard to see and that's the one for the front brakes.

Lee said:

Sorry for asking twice, but did you get a good look at both chambers of the back reservoir?
The inside chamber is hard to see and that's the one for the front brakes.

View attachment 86430

Click to expand...

I’m not seeing a second reservoir on this.