The Fuel Temperature Sensor (FTS) is installed on the fuel supplying line and measures the temperature of the fuel supplied from the fuel tank (via fuel filter). The FTS uses a thermistor which resistance is in inverse proportion to the temperature (NTC: Negative Temperature Coefficient). With this signal, the ECM can adjust the injection amount.

At high temperature, vapor-lock in fuel line or oil membrane destruction may appear. Especially oil membrane destruction deteriorates fuel's lubrication performance and it may damage the high pressure fuel pump and the injector.