Step on rear brake and red warning triangle light up and stays lit until I shut down

Had my nearest dealer change the brake fluid on my bike. At first I had a problem because they hadn’t tightened one of the bleeders properly and I kept getting an ABS message. I took it back and they rebled the line and tightened the bleeder and everything was fine at first. However I soon found out whenever I stepped on the rear brake pedal my dashboard red triangular warning light comes on and stays on until the bike is turned off and restarted. It only happens when I step on the rear brake pedal. This is a 2006 r1200rt With linked whizzy brakes. The brake light and brakes seem to operate well and there is no ABS problem.

Check the obvious stuff first, like the brake light bulb to verify that it is working. Then take it back to the dealer for a re-visit on the bleeding process, and ask that they perform the pressure test that is recommended at the end of the bleeding procedure.

Best,

DG

probably low fluid level in the servo unit UNDER the tank....

Giant PITA to bleed the brakes on the whizzy models...

edit...i would strongly recommend you find another service location...it is apparent that they are clueless about BMW brakes...AND leaving a bleeder loose is UNACCEPTABLE!!!

glwestcott said:

Had my nearest dealer change the brake fluid on my bike. At first I had a problem because they hadn’t tightened one of the bleeders properly and I kept getting an ABS message. I took it back and they rebled the line and tightened the bleeder and everything was fine at first. However I soon found out whenever I stepped on the rear brake pedal my dashboard red triangular warning light comes on and stays on until the bike is turned off and restarted. It only happens when I step on the rear brake pedal. This is a 2006 r1200rt With linked whizzy brakes. The brake light and brakes seem to operate well and there is no ABS problem.

Click to expand...

Info below is only valid for models having the iABS servo-assisted modulator - this was installed on most R and K models between 2002-2006 for USA market (Europe / Canada got these 1 year earlier).

By design, on iABS servos models, the modulator internal pressure sensors will sense that you have created hydraulic pressure using pedal application (or brake lever) , thus it can activate the servos AND the brake-light EVEN IF THE SWITCH IS DEFECTIVE. The General-Warning (RED triangle) and the resulting fault code in memory is there to warn you that something is not working as it should. With engine / ignition OFF, listen carefully for a mechanical "click" of the brake pedal switch during the first 3mm of travel (roughly 1/8 inch).

This logic and behavior is one part of the internal diagnostic and fault tracking of iABS.. On these modulator, it is expected the switch will ALWAYS activate early - before a certain pressure level is reached - otherwise a fault is shown and logged in memory. If the switch is defective of activates very late in pedal movement, you will this single RED triangle warning steady (no flash). HOWEVER, if this warning is visible with another warning at same time (the ABS red warning) THEN the fault code is something else.

BY THE WAY, this fault above is very different than if you had the Rear-Brake-Switch disconnected (or a wire cut): in such case, the fault would appear immediately after ignition ON (during the ABS modulator internal self check) AND it would show as a fast flashing ABS warning. The design of these switch is such that they have continuity at rest - basically the opposite logic of most other brake systems on any other make. Thus immediately after ignition ON, the ABS modulator can do a check if both brake switches are connected - this is the reason why the owners manual tells you to stay OFF the brakes when you turn ignition ON (like if you are parked in an incline).

So the bike went back to the shop. They are going to redo the whole bleed and see how it goes.

Got it back. This time they did the whole brake bleed over remembering to tighten the bleeders and ran BMW brake diagnostic. Wonder of wonders everything works again - no fault lights and whizzy brakes are back to sounding like they did before I took the bike in to begin with. I’m a bit more than pissed about the whole experience.

This was a very helpful thread thank you very much I replaced the brake microswitch on my 2005 K1200S and the red triangle solid light is gone