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 troubleshootingTest mode procedure
Hint:
By switching the skid control ecu from normal mode to
test mode, abnormality detection sensitivity is enhanced
and troubleshooting can be conducted efficiently.
Perform a sensor check in test mode after the speed
sensor or sensor rotor has been repaired or replaced.
If the igniti ...
Exhaust pipe
Components
Removal
Disconnect cable from negative battery terminal
Caution:
Wait at least 90 seconds after disconnecting the
cable from the negative (-) battery terminal to
prevent airbag and seat belt pretensioner activation.
Remove heated oxygen sensor (for bank 1
sensor 2) (s ...
Oxygen (a/f) sensor pumping current circuit
Description
Refer to dtc p2195 (see page es-292).
Monitor description
The air-fuel ratio (a/f) sensor varies its output voltage in proportion to
the air-fuel ratio. If the a/f sensor
impedance (alternating current resistance) or output voltage deviates greatly
from the standard range ...