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 troubleshootingIg power source circuit
Description
This is the main power source supplied to the air conditioning amplifier when
the ignition switch is on
(ig). This power source is used for operating components, such as the air
conditioning amplifier and
servo motors.
Wiring diagram
Inspection procedure
Inspect fuse (ec ...
On-vehicle inspection
Notice:
Perform the maf meter inspection according to the
procedures below.
Only replace the maf meter when both the long
ft#1 value and maf value in the data list (with the
engine stopped) are not within the normal operating
range.
Inspect mass air flow meter
Perform c ...
Basic audio operations
Basic audio operations and functions common to each mode are
explained in this section.
Operating the audio system
Press this knob to turn the
audio system on and off, and
turn it to adjust the volume.
Press this button to eject a disc
Insert a disc into the disc slot
Press to pa ...