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 troubleshootingDiagnosis system
Description
The center airbag sensor controls the functions of the
supplemental restraint system (srs) on the vehicle.
Data of the srs can be read in the data link connector
3 (dlc3) of the vehicle. When the system seems to be
malfunctioning, use the intelligent tester to check for a
ma ...
Ecm communication circuit malfunction
Description
The circuit is used to send trc and vsc control information from the skid
control ecu to the ecm, and
engine control information from the ecm to the skid control ecu.
Inspection procedure
Hint:
Check that the part numbers of the installed ecm and skid control ecu are
cor ...
Dtc check / clear
Check dtc (using sst (check wire))
Check the dtcs (present trouble code).
Turn the ignition switch on, and wait for
approximately 60 seconds.
Using sst, connect terminals 13(tc) and 4(cg)
of the dlc3.
Sst 09843-18040
Notice:
Connect the terminals to the correct
positio ...