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 troubleshootingBrake warning light does not come on
Wiring diagram
Refer to the brake warning light circuit (see page bc-145).
Inspection procedure
Check can communication system
Check if the can communication system dtc is output
(see page ca-34).
Result
Perform active test by intelligent tester (brake warning light)
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Torque converter clutch solenoid circuit
Description
The shift solenoid valve dsl is turned on and off by signals from the ecm to
control the hydraulic
pressure acting on the lock-up relay valve, which then controls operation of the
lock-up clutch.
Fail-safe function:
if the ecm detects a malfunction, it turns the shift sol ...
Removal
Hint:
Use the same procedures for the rh side and lh side.
The procedures listed below are for the lh side.
Remove front pillar cover sub-assembly upper lh
Using a moulding remover, detach the 3 clips and
remove the pillar cover.
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