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 troubleshootingRoad test
Problem symptom confirmation
Based on the result of the customer problem
analysis, try to reproduce the symptoms. If the
problem is that the transaxle does not shift up, shift
down, or the shift point is too high or too low,
conduct the following road test referring to the
automat ...
Check and replace ecu
Notice:
The connector should not be disconnected from
the ecu. Perform the inspection from the
backside of the connector on the wire harness
side.
When no measuring condition is specified,
perform the inspection with the engine stopped
and the ignition switch on.
Check that the con ...
Fuel tank cap
Inspection
Inspect fuel tank cap assembly
Visually check that the cap and gasket are not
deformed or damaged.
If the result is not as specified, replace the cap
assembly or gasket.
Remove the gasket from the exhaust manifold.
...