Transponder chips were introduced into car keys in the late 90s to enhance vehicle security. These chips, embedded in the key’s plastic cover, send a message to the car’s transceiver, confirming the key’s legitimacy. This system was designed to thwart hot-wiring and slide hammer attacks. Simply copying the key blade’s bitting won’t enable the car to start; the proper transponder chip is also necessary.

When the right key is inserted into the ignition, an electric charge powers the transponder chip, allowing it to send a message to the car’s transceiver. If the transponder isn’t programmed or absent, the transceiver won’t receive the correct message, and the car won’t start. Transponder key programming often goes hand-in-hand with cutting a new car key, but it can be a separate service as well. Existing transponder keys can be removed from the car’s computer, so only new ones will work.