Did they clear the code? I always recommend that if your vehicle can store freeze data to leave the code there for the diagnostic technician. Sometimes it can be helpful.

Could be an electrical problem, could be a mechanical or hydraulic problem. The transmission could be failing or a solenoid/switch could be failing. It is possible to have rats chew on wires that cause problems, too.

The computer definately saw a problem and I would never recommend to clear the code and forget it. Never know where you are going to be when the car fails. If you can have the system checked out, you'd probably be better off. I'd stay away from a "quicky, cheapy" trans shop and probably let a Honda dealer check it out.