The engine immobiliser system is designed to prevent the vehicle from being stolen. This system uses a transponder key ecu that stores the key codes of authorized ignition keys. If an attempt is made to start the engine using an unauthorized key, the ecu sends a signal to the ecm to prohibit fuel delivery and ignition, effectively disabling the engine.

The transponder key coil receives this signal, the transponder key amplifier amplifies it, and then the signal is transmitted to the ecu. The ecu matches the key's id code with the vehicle's id code, which was previously registered in the ecu and then communicates the results to the ecm using sfi communication.
Engine immobiliser system
How to proceed with troubleshootingThe keys
The following keys are provided with the vehicle.
Vehicles without a smart key system (type a)
Master keys
Operating the wireless remote control
function
Valet key
Key number plate
Vehicles without a smart key system (type b)
Master keys
Operating the wireless r ...
Customization
Customizable features
Your vehicle includes a variety of electronic features that can be
personalized to your preferences. The settings of these features
can be changed by using the steering wheel switches, entune
premium audio with navigation or entune audio, or at your
toyota dealer.
Customi ...
Emission inspection
and maintenance (i/m)
programs
Some states have vehicle emission inspection programs which
include obd (on board diagnostics) checks. The obd system
monitors the operation of the emission control system.
If the malfunction indicator lamp comes on
The obd system determines that a problem exists somewhere in the
emission contr ...