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 troubleshootingTerminals of ecu (2005/11-2006/01)
Notice:
Turn the ignition switch off before measuring the
resistances of the main wire and the branch wire.
After the ignition switch is turned off, check that the
key reminder warning system and light reminder
warning system are not in operation.
Before measuring the resistance, leave ...
Inspection
Inspect front seat outer belt assembly
Notice:
Do not disassemble the retractor.
Before installing the outer belt, check the elr.
When the inclination of the retractor is 15Ð or
less, check that the belt can be pulled from the
retractor. When the inclination of the retractor ...
Open in occupant classification ecu battery positive line
Description
Dtc b1794 is set when a malfunction is detected in the occupant
classification ecu battery positive line.
Wiring diagram
Inspection procedure
Check for dtc
Turn the ignition switch on.
Clear the dtcs (see page rs-249).
Hint:
First clear dtcs stored in the ...