Need help solving ABS problem
 

I am trying to diagnose a persistent ABS failure -- important since a modulator is $2400!

Just about every ride now at some point in the ride the ABS flashes 4 Hz along with a steady warning light, indicating that one brake is in the residual mode (it's the rear one). The fault code is indicating an abs pump problem. In my garage, the speedo jumps way up when I pump the rear brake. Is this normal or related to the ABS problem?

Anybody found a solution other than replacing the modulator? I have done all the normal troubleshooting - battery, brake switches and fluid.

The speedo shouldn't do that, so I'd look for a bad ground or other other connection causing voltage to be or not-be where it shouldn't or should-be. I know that's super vague, but in general, when you have that sort of symptom (one electrical issue manifesting in a seemingly unrelated area) there tends to be a short, open, or resistive connection (more likely the latter)

I'd want to see that speedo symptom go away before I layed out 2.4k. If anyone knows differently, I'm all ears. Don't have a diagram in front of me right now.

Which bike ? Which ABS System ? (VIN)

If it's a R1100S with a integral ABS System from FTE I'd suggest the same as Roger did above (excluding an electrical problem from the list of possible reasons).

Thanks for the tips. Bike is an '02. It's the ABS-I system (servo). If anyone has a used one for sale, please PM me. tnx...

ps this modulator is used on the 1150 series bikes, too.

I too think I would hold your cash until you find out what is making other things malfunction, could be as simple as a battery issue, or loose connection.