Fuel Tank Pressure Sensor
WARNING: This page is about a different car, the 2003 Pontiac Grand Prix, 2003 Chevrolet Malibu, and 2003 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
The Fuel Tank Pressure (FTP) sensor mounted on top of the fuel sender assembly, measures the difference between the pressure or vacuum in the fuel tank and outside air pressure. See Figure . The PCM provides a 5-volt reference and a ground to the FTP sensor. The FTP sensor provides a signal voltage back to the control module that can vary between 0.1-4.9 volts. As FTP increases, FTP sensor voltage decreases, high pressure - low voltage. As FTP decreases, FTP voltage increases, low pressure or vacuum - high voltage.