My red BRAKE and amber ABS warning lights are on

Both work fine. What could cause both lights to come on at the same time? I just fixed the parking brake sensor which was broken. The car used to "ding" for about 5 seconds every time I started driving from a stop(thinking my p brake was on). Now it doesn't "ding" anymore, but the lights still come on. I thought this was the problem, but clearly there is something else.

The brake pads are due for replacement, but would that cause both lights to come on? Some details...
I tested the ABS on a gravel road and they work fine. Brake fluid is not leaking and is at a good level(room in reservoir for when I replace the pads).

Lights are off if I start the car holding the brake pedal down. They come on simultaneously when I lift off the brake to drive.

Thanks