How do you reset immobilizer on 2003 Toyota Echo?

To reset the immobilizer on a 2003 Toyota Echo, first ensure that you have the correct key for the vehicle. Insert the key into the ignition and turn it to the "ON" position without starting the engine. Leave it in this position for about 10 minutes until the security light goes off, then turn the key back to the "OFF" position. Repeat this process two more times for a total of three cycles, and then attempt to start the engine. If issues persist, consult a professional mechanic or dealership for further assistance.