Rear brake weirdness, no rear ABS, and ABS light on- 2013 w/70K miles.

Last fall had the ABS light come on after I used the rear brake alone, shut off bike and restarted which reset it and no more problems.

Just dragged the bike out for spring and same thing, with high effort to depress the rear brake pedal at first and ABS light comes on. Front ABS works but as soon as I use rear brake alone ABS light comes on and no ABS front or rear. Linked brakes may not be working, bike stops good but using the brake lever alone I can't activate rear ABS or lock up rear wheel.

Bled brakes both ends and effort to press pedal down reduced but same problems. Activated ABS pump several times with the wire across the black and blue terminals several times and can feel both front and rear brakes pulsing but the misbehavior continues.

Any suggestions? TIA.

I'd say start with checking your error codes for the ABS... could be something simple like the rear wheel sensor.
Mr. BR

I’ve seen this (or something similar). Check the magnetic ring at the rear hub. Make sure it’s clean. But the issue ‘might’ be damage to the wire. From the sensor up to the harness up under the seat if I remember correctly.
If you have ever ridden in dirt with a high iron content and dusty… it will collect on the wheel ABS rings and cause issues. This has happened to me before. I just yanked the wheel, cleaned the ring and good-to-go.
Maybe these are just a few ideas.

And as someone suggested. Is there a dash code ? What is the code ?

Thanks, checked codes and first try I got a bunch, cleared codes and after a test ride the symptoms returned and got code 73- Difference between rear brake caliper and master cylinder pressure.

From what you're describing, it sounds like your ABS pump is taking a poo poo.

scott123007 said:

From what you're describing, it sounds like your ABS pump is taking a poo poo.

Click to expand...

Unfortunately I agree. The high effort to depress the brake lever is the give away.

The ABS module is failing (there are usually 2 failures: the pedal goes to the floor without braking or the pedal becomes very hard...but I think there is a revealing fact. That fault 73, …I don't remember anyone mentioning it before (in other abs module fail). but it clarifies things somewhat... when the combined brake acts, there must be a valve that blocks the circuit to the rear pump, so that the pressure exerted by the electric motor is route “only” to the rear caliper (otherwise it would also go to the rear pump and the rear reservoir….the valve that must be blocking must be that one, and it prevents the pressure exerted on the rear pump (not combinated brake) going to the caliper (which increases the pressure inside of the module and activate the pressure sensor)...unequivocally the ABS module is failing, but probably not per se...with 70k miles, you have surely changed the pads 3,4 or maybe 5 or more times, and I wonder...did you always loosen the bleeders when you pushed the pistons?
The ABS module always fails only in the rear brake...and not only in the S10...or in Yamaha, all other brands and models with combined brakes, have failures in the rear brake
PD: That pressure sensor must measure the pressure that enters to the module and the pressure that leaves it towards the caliper....if everything works well, and you step on the brake pedal or exert maximum pressure on the front brake lever, If everything is working well…the sensor “will not activate”