ASC/TRAC light after rotor/pad change

I just changed the rear rotors and pads on a 2010. Mileage is 145,000, owned since new. It seems the ASC/TRAC light now flashes when pedal is depressed (put car in drive in garage - depress pedal - one beep and light flashes). I had trouble with one of the the caliper pistions, and screwed it all the way out and lost 1/2 teaspoon of brake fluid, so I may have introduced air into the line. Would this cause this? Is there anything unusual about bleeding brakes (as compared to non-regenerative braking cars)?