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 troubleshootingInside vehicle
General maintenance
Performing the following maintenance checks on the vehicle
is the owner's responsibility. The owner may perform the
maintenance or take the vehicle to a service center. Check
the parts of the vehicle described below on a daily basis. In
most cases, special tools are not requ ...
Components
...
Random / multiple cylinder misfire detected
Description
When the engine misfires, high concentrations of hydrocarbons (hc) enter the
exhaust gas. Extremely
high hc concentration levels can cause increases in exhaust emission levels.
High concentrations of hc
can also cause increases in the three-way catalytic converter (twc) te ...