Basic primer: On the non-servo (2007+) system the pump motor turns on if ABS is activated, or when the front brake is applied (when the front brake is applied tho motor is used to generate pressure to activate the rear brake, in order to provide linked braking.) You can test this by placing the bike on the centerstand, turning the key to the run position, then spinning the rear wheel by hand and applying the front brake -- you should hear the pump motor run for a few seconds and the rear wheel will stop. If not, and you have a brake failure warning light then you probably have sticking brushes... very common. You can confirm with a GS911 if available, you'll see a 'low voltage' or' pump motor circuit' ABS fault.
There are instructions available online to disassemble the motor from the valve module in order to repair. Many just free up the brushes and reassemble, but it's almost guaranteed any quickie repair method will only result in your having to do it all over again a few months later (if it lasts that long.) The only proper repair involves gaining full access to the brush baseplate and it's necessary to remove the pressed-on bearing and alter the brushes in order to do the job properly, so it gets a little complicated. So your two choices are either the Full Monty in your home shop, or send it to Module Masters where for $250 they will do a proper repair/rebuild and provide a 5-year warranty. I guess there's the third option of taking it to your dealer, but the absurd repair cost is impractical.
Removing and replacing the ABS module isn't difficult, but a GS911 is required to properly bleed the ABS unit after installation since it will be dry. I've read that some manage to bleed the unit by activating ABS on the road, bleeding, and repeating many times but that sounds like a royal PITA. Better to borrow a GS911 if you don't have one.
In the meantime you can ride the bike safely, you just won't have linked braking or ABS.
Last edited by smiller; Jun 24th, 2018 at 10:23 pm.