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 troubleshootingDriver side seat belt buckle switch circuit malfunction
Description
The driver side seat belt buckle switch circuit consists of the center airbag
sensor and the front seat inner
belt lh.
Dtc b1655/37 is recorded when a malfunction is detected in the driver side seat
belt buckle switch circuit.
Wiring diagram
Inspection procedure
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Terminals of ecu (2005/11-2006/01)
Check air conditioning amplifier
Measure the voltage and resistance of the
connectors.
Hint:
Check from the rear of the connector while it is
connected to the air conditioning amplifier.
Using an oscilloscope, check waveform 1.
Compressor and pulley operation signa ...
Ecu power source circuit
Description
This is the power source for the tire pressure warning ecu.
Wiring diagram
Inspection procedure
Notice:
It is necessary to register an id code after replacing the tire pressure
monitor valve and/or the tire
pressure warning ecu (see page tw-9).
Inspect fuse (ecu-ig1)
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