We bought two new keys for our Honda Odyssey over a year ago, they were cut and programmed at the dealership. Yesterday, one of the keys stopped working, it'll still open the van, turn in the ignition and roll the engine over, but the engine won't start, as if there was no spark. The other key however works fine, starts the van like it always has. What would cause one key to stop working?
One of two things. Either the key itself is fouled (electronics or transmitter is broken) or the vehicle itself has lost track of the key. In the first scenario, you'll need to get a new key and get it programmed. In the second scenario, you'll most likely need to take it back to the dealership and have it reprogrammed. The first scenario seems more likely.