my '04 is 2.5 years old. of late (the last 2 weeks) there have been a few failures for the smart entry to work and/or the keyless ignition to recognize the presence of the key in my pocket (the little logo shows on the screen indicating no key in the house), and then after repeat trying, both door and start will work. this has happened with both my key fobs, but only a few times at the door and only once with the start process. could the keys need batteries? has anyone had to replace batteries in their keys?