How to reset the "Maintenance Required" light...
This light is a mileage counter, to remind you to change your oil at the 5,000 mile interval Toyota recommends in the owner's manual. After 4,500 miles since it was last reset, it will flash for 12 seconds after every "ignition on" event. After 5,000 miles since last reset, it will stay on constant.
Reset instructions are in the owner's manual. They're also posted here.
With the key on, make sure the main odometer is displayed, and not one of the trip odometers. Turn the key off, so that all displays go dark. Press and hold the trip odometer reset button, and while continuing to hold the button, turn the key back to on (no need to start the engine). You'll see a series of countdowns, like this (keep holding the button):
When the zeros show, it's reset. You can release the trip reset button and turn the key off.
Moderators, would someone mind making this thread a sticky? It seems to come up often enough.
2011 Toyota Camry (Sandy Beach Metallic)
2005 Acura MDX Touring (Billet Silver Metallic)