Thanks guys!

I know it isn't the gas cap; I've seen that happen before, but it usually throws the check engine light too, and never the Brake! light. This was different. It wasn't the battery either. It has been really cold here, and my battery died three weeks ago, so I'm running a brand new Optima Red Top.

I went with the only code that made sense, and replaced the driver's side wheel speed sensor last night. I cleared the codes and drove up and down the mountain on which I live - drove about ten miles. So far, so good (finger's crossed) - No codes or lights.

The new sensor seems to have done the trick. I'll update if the issue returns . . . but hopefully not. Thanks everybody!