99 legacy wagon 2.2 L (210,000 mi) recently can feel ABS come on just before the car comes to a complete stop and skidding is definitely not occuring.  Any thoughts?

Caliper sticking maybe. Try greasing the rails. Have you ever flushed the brake fluid?

Does the ABS light turn off shortly after you start up the vehicle? From what you described one guess might be a wheel speed sensor, especially if it has a fair amount of crud built up around the tone wheel. At speed the sensor might detecting the tone wheel just fine but at really low speed i.e. just before it stops if it's having trouble reading the tone wheel, i.e. the pulse amplitudes being too low, it may be assuming that wheel has locked up and then the ABS kicks in.

I will check out the sensors and tone wheels.  No, ive never flushed the brake fluid.

This usually happens when one speed sensor is dropping the signal. The ABS thinks one wheel is locking.

This can be either a bad sensor or a corroded connection in the sensor plug, or a broken wire. I've seen all three cause this.

 

Check the sensors and tone wheels for crud/dirt stuck in/on them, and check the wiring for any cuts or breaks in the insulation.

thanks for the tips, will start an inspection.  and yes the abs light goes off shortly after starting.

I discovered an over inflated tire will make the ABS hyper active too.