The diagnostic code P0452 OBD2 refers to a malfunction of the emission system. The Powertrain Control Module (PCM) takes into account the signal from the Fuel Tank Pressure Sensor (FTP) to detect changes in the internal pressure of the fuel tank. It should be noted that the position of this sensor will depend on the model of your vehicle, since it may be located in the fuel purge line at the top of the fuel tank.
When the Powertrain Control Module (PCM) determines that the emissions system pressure is below the expected level, it is not the FTP (Fuel Tank Pressure) sensor that is the only cause, as it indicates that there is a problem in the system.
The FTP sensor is mainly used to control emissions since the fuel tank usually tends to have fuel vapor pressure at the time the temperature is high, and a vacuum if the load is low. Then the Fuel Tank Pressure Sensor (FTP) sends a voltage signal to the PCM for analysis. However, the current value varies with pressure or vacuum. Although this DTC code refers to all vehicles, it has a difference in the sensor output. Likewise, all of these sensors convert pressure to a voltage, which will increase or decrease with pressure or vacuum.