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 troubleshootingCoolant
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 ...
Vehicle speed signal error (test mode dtc)
Description
The tire pressure warning ecu receives a speed signal from the combination
meter. This dtc is stored
upon entering test mode, and cleared when a vehicle speed signal of 12 mph (20
km/h) is detected for 3
seconds or more. The dtc is output only in test mode.
Wiring diagram ...
Short in front passenger side - side squib circuit
Description
The front passenger side - side squib circuit consists of the center airbag
sensor and the front seat side
airbag rh.
The circuit instructs the srs to deploy when the deployment conditions are met.
These dtcs are recorded when a malfunction is detected in the front passenge ...