Subaru Problems? Ask a Mechanic for Answers ASAP
What do you mean by the brake won't engage? You can't set the parking brake?
I am glad to hear all the lights cleared. It sounds like the check engine light got all the others going, with the exception of the parking brake light. Normally when the check engine light comes on the traction control (skid marks) and cruise control lights will flash or come on. They are disabled as a safety feature since the car has an electronic throttle body.
More then likely when it slipped into neutral a code was set off in the transmission control module asking that the check engine light be illuminated.
At any rate, glad you decided to drive it, I would have told you to go ahead. Sounds like the system reset itself after you cycled the key. Actually it slipping into neutral likely fooled the computers!