System Description
WARNING: This page is about a different car, the 2006 Lexus RX 400h. However, it is still accessible from the selected car via links, so may be relevant.
The engine immobilizer system has been designed to prevent the vehicle from being stolen.
This system uses a transponder key ECU that stores the key code of the authorized ignition key. If an attempt is made to start the engine using a non-authorized key, the transponder key ECU sends a signal to the hybrid vehicle control ECU to prohibit fuel delivery and ignition, effectively disabling the engine.