The key recognition ECU checks the transponder code built into the key remote and compares it with the code stored in the ECU. If the codes match, the key recognition ECU communicates with the power system ECU and the steering column lock ECU to turn on the power and unlock the steering column.
After confirming the steering column unlock, the immobilizer is disabled and a signal is sent to the engine ECU to allow the engine to start.
Pic. 1.70. Location of the main components of the electronic immobilizer system