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 troubleshootingIf your vehicle needs
to be towed
If towing is necessary, we recommend having your vehicle
towed by your toyota dealer or commercial towing service,
using a wheel-lift type truck or flatbed truck.
Use a safety chain system for all towing, and abide by all state/
provincial and local laws.
2Wd models: if towing your vehicle ...
Automatic
air conditioning system
Air outlets and fan speed are automatically adjusted according
to the temperature setting.
Driver’s side temperature control
dial
Automatic mode button
Micro dust and pollen filter
mode button
Driver’s side temperature setting
display
Fan speed display
Air outlet display ...
Brk relay
On-vehicle inspection
Inspect brk relay
Remove the brk relay from the engine room no. 1
Relay block.
Measure the resistance of the relay.
Standard resistance
If the result is not as specified, replace the relay. ...