Fuel Tank Pressure Sensor
WARNING: This page is about a different car, the 2009 GMC Canyon and 2009 Chevrolet Colorado. However, it is still accessible from the selected car via links, so may be relevant.
The fuel tank pressure (FTP) sensor measures the difference between the pressure or vacuum in the fuel tank and outside air pressure. The control module 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. A high FTP sensor voltage indicates a low fuel tank pressure or vacuum. A low FTP sensor voltage indicates a high fuel tank pressure.