Smart Keys - Backup in Case of Low Battery

Backup in Case of Low Battery

If the battery in the Smart key becomes depleted, it is necessary for there to be a backup method of opening and starting the vehicle. Opening is achieved by an emergency (fully mechanical) key blade usually hidden in the Smart key. On some cars starting is achieved by a transponder inside the Smart key that does not need batteries to work. The user either has to put the key in a slot or hold it near a special area on the cockpit, where there is another LF antenna (transponder coil) hidden behind to compensate for a weakened fob battery.

Slots have proven to be problematic, as they can go wrong and the key becomes locked in and cannot be removed. Another problem with the slot is it can't compensate for a fob battery below certain operating threshold. Most smartkey batteries are temperature sensitive causing the fob to become intermittent, fully functional, or inoperative all in the same day.