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 troubleshootingOccupant classification ecu
Components
On-vehicle inspection
Inspect occupant classification ecu
(vehicle not involved in collision)
Perform a diagnostic system check (see page rs-
236).
Inspect occupant classification ecu
(vehicle involved in collision)
Perform a diagnostic system check (see p ...
Door control transmitter module
Components
Removal
Remove transmitter housing cover
Notice:
Take extra care when handling these precision
electronic components.
Twist the screwdriver in the direction of the arrow
mark in the illustration, and open the transmitter
housing cover.
Notice:
Do not forcibly pry ...
Programming HomeLink
â– Before programming
HomeLink
During programming, it is possible
that garage doors,
gates, or other devices may
operate. For this reason,
make sure that people and
objects are clear of the
garage door or other devices
to prevent injury or other
potential harm.
It is recommended that a n ...