[marc]

I assume you have an '04, '05, or '06 bike. There are no fuses. There are a couple of things you can try but in all honesty they rarely help.

1) Do a complete brake fluid flush. You'll need a GS-911 or the dealer diagnostics tool to exercise the ABS when as part of the flush process. It is a time consuming job. The GS-911 can also tell you if the ABS unit is reporting any fault codes.

2) See Integral ABS - CAN (servo brakes) "Pressure in rear/front circuit too low"

3) See https://advrider.com/f/threads/abs-modulator-failures.653191/#post-15016545

Edit: If your bike is 2007 or newer the above does not apply because you don't have the power assist servo ABS. The later ABS units have issues with the motor drive brushes. Let us know your bike.

 

[marc]

The flush process on bikes with "whizzy" brakes is complicated because there are separate wheel and control circuits that need to be flushed. The reservoir on the handlebar, for example, does NOT directly connect to the front calipers. Some, not realizing that, have sucked the reservoirs located in the ABS unit dry while wondering why the fluid in the reservoir never drops.

Read this doc ==> http://users.rcn.com/dehager/service/service_abs3.pdf

to understand the brake flush procedure needed for your bike.

I work slow. I allocated about 4 hours to flush brakes on my '05. I did that every other year.

 

[marc]

Though it's still a good idea to flush the brake fluid if it's been more than two years.

Yup. One of the issues of the whizzy brakes is that the power assist can hide poorly bled brakes and/or brake fluid that is well past its time. A procedure I followed after a brake bleed was to ride down a long local street and kill the ignition then try to stop the bike using what BMW calls residual braking power. That's the brake power you get when the power assist isn't on. If you are pulling the lever to the bar and the bike isn't slowing very much you need to re-visit your brake flush. Yes, once I needed to re-visit my brake flush. :surprise:

That procedure also reminds you of what it feels like when the power assist stops so you won't be overly surprised should it fail for some reason while on a ride.