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 troubleshootingPressure control solenoid "A" electrical (shift solenoid valve sl1)
Description
Shifting from 1st to o/d is performed in combination with the on and off
operation of the shift solenoid
valves sl1 and sl2, which are controlled by the ecm. If an open or short circuit
occurs in any of the shift
solenoid valves, the ecm controls the remaining normal shift soleno ...
Precaution
If any of following conditions are met,
keep engine idling with a/c on (engine
speed at less than 2000 rpm) for at least 1
minute:
Refrigerant gas has been refilled or a/c parts have
been replaced.
A long time has elapsed since the engine was
stopped.
Notice:
If the engine s ...
Air fuel ratio sensor
Components
On-vehicle inspection
Check air fuel ratio compensation system
Connect the intelligent tester to the dlc3.
Turn the ignition switch on.
Select the following menu items: data list / a/fs b1
s1 and o2s b1 s2.
Warm up the a/f sensor with the engine speed at
2,500 ...