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 troubleshootingSteering column assembly
Components
Removal
Caution:
Some of these service operations affect the srs airbag
system. Read the precautionary notices concerning the
srs airbag system before servicing the steering column
(see page rs-1).
Place front wheels facing straight ahead
Disconnect cab ...
Disposal
Hint:
When scrapping a vehicle equipped with an srs or disposing
of the curtain shield airbag assembly, be sure to deploy the
airbag first in accordance with the procedure described
below. If any abnormality occurs with the airbag deployment,
contact the service dept. Of toyota motor sales,
u. ...
For vehicles equipped with catalytic converter caution:
If a large amount of unburned gasoline or gasoline
vapors flow into the converter, it may cause
overheating and create a fire hazard. To prevent this,
observe the following precautions.
Use only unleaded gasoline.
Avoid idling the engine for more than 20 minutes.
Avoid performing unnecess ...