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 troubleshootingRemoval (2005/11-2006/01)
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 front door scuff plate lh
Using a screwdriver, detach the 10 cla ...
Rear occupant classification sensor rh circuit malfunction
Description
The rear occupant classification sensor rh circuit consists of the occupant
classification ecu and the
rear occupant classification sensor rh.
Dtc b1783 is recorded when a malfunction is detected in the rear occupant
classification sensor rh
circuit.
Wiring diagram
...
Transmission range sensor circuit malfunction (prndl input)
Description
The park/neutral position (pnp) switch detects the shift lever position and
sends signals to the ecm.
Monitor description
These dtcs indicate a problem with the park/neutral position switch and the
wire harness in the park/
neutral position switch circuit.
The park/neu ...