System Description/Monitoring Procedure
WARNING: This page is about a different car, the 2011 Suzuki SX4. However, it is still accessible from the selected car via links, so may be relevant.
The engine coolant temperature is estimated to model accumulated combustion heat value since engine start (based on mass intake air flow) and radiation heat value (radiation from engine, radiation when fuel shut-off, etc.). When estimated temperature reaches the specified temperature and the measured temperature is lower than criteria, the malfunction is detected.