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 troubleshootingGeneral maintenance (2005/11-2006/01)
Inspect drive belt (see page em-6)
Replace spark plugs (see page ig-7)
Replace air cleaner filter
Remove the air filter.
Visually check that the air filter is not excessively
damaged or oily.
Replace the air filter with a new one, if necessary.
Replace engine oil and oil fil ...
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.
...
Coolant
Replacement
Remove no. 1 Engine under cover
Drain engine coolant
Loosen the radiator drain cock plug.
Hint:
Collect the coolant in a container and dispose of it
according to the regulations in your area.
Remove the radiator reservoir cap.
Caution:
Do not remove the radiator ...