How do you reset a Lexus key?

The answer depends upon which ECU your vehicle has.

One ECU type ( 32 bit ) is programmed via the OBD-II port, and ECU RESET, KEYS DELETED, KEYS ADDED etc. Locksmiths will have one of 3 diagnostic tools necessary for this task, along with the needed RFID chip keys.

The other type ( 16 bit ) has no OBD-II Path to the security modes on the ECU and must be REFLASHED. IT need not be replaced due to lost keys. If you STILL HAVE A MASTER KEY, the programming of additional keys one one of the two types is done on-board, and without diagnostic equipment.

SOME dealerships will do the reflash on the 16 bit ECU, but many will tell you you MUST buy a new ECU.

A good locksmith can do the job efficiently, often onsite, with more options than a dealer might offer.