Like a number of us have experienced, check the front wheels for a stone or pebble lodged between the brake caliper and the rotor. We've experienced a chattering/grinding sound. There's a thread on this in the problems sub-category.
When I took my truck to the dealer to have it checked out, I got an explanation from the service manager that this was Not an Uncommon event, with Honda's caliper housing design; happens on other Hondas, as well.
When I took my truck to the dealer to have it checked out, I got an explanation from the service manager that this was Not an Uncommon event, with Honda's caliper housing design; happens on other Hondas, as well.