In 1998, Toyota and Lexus began equipping their most popular vehicles with a transponder based immobilizer system. The keys have an embedded transponder chip that must be recognized by the vehicle ECM (engine control module) unit before it will start. The electronics that controls this function is an essential part of the onboard computer system. The starting, fuel, and ignition systems of the vehicle are not functional until the system recognizes a pre-registered key.
Having extra keys made is simple if the owner is in possession of a working master key for the vehicle. The mechanical cuts can be copied to the new transponder key blank. The new copy of the key will lock and unlock the doors, open the trunk, and turn in the ignition, but it will not start the vehicle until the transponder chip in the head of the is programmed into the vehicle. This is accomplished by using one of the master keys already registered in vehicle’s memory to begin the programming process. This can be done with any of the pre registered master keys, valet keys will not initiate this process.
If a key is completely lost or all you have is a valet key the only way to obtain a new key is have the ECM (engine control module) replaced or have the ECM (engine control module) re-flashed by Express Locksmiths.
Having this done by the dealer can cost as much as $1500.
Express Locksmiths can re-flash your ECM for $495.