A faulty brake master cylinder reservoir filter can cause the brake system indicator to illuminate after a cold start and then go off. Replacement of the reservoir filter will commonly fix this problem.Google+
Car Problem Reports
Honda Accord Faulty Master Cylinder Resevoir Filter Can Cause Brake Light After Cold Start
Honda Accord Problem
Average Mileage: 114,185 mi (75,000 mi - 147,000 mi)
Visitor, 2000 Honda Accord, 126,000 mi
This happened last winter and is happening again this winter. I don't believe it is a real problem but my state inspection is due and I will certianly fail with the brake light active.
Visitor, 2001 Honda Accord, 75,000 mi
haven't fixed the problem. light goes on and off but brakes are actually fine
Visitor, 2002 Honda Accord, 100,000 mi
Brake indicator comes on every cold morning. Letting the car warm up turns the indicator off. It's been to several mechanics and yes it can be fixed, but if the light doesn't bother you (I personally couldn't care less) then as the mechanics said it doesn't really effect anything. My cars up to 125,000 no issues other than routine maintenance. If a sensor is all I have to worry about I call that solid construction.
happens more in the cold weather.