Fuel Tank Pressure Sensor
WARNING: This page is about a different car, the 2003 Pontiac Sunfire, 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, and 2003 Chevrolet Cavalier. 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 air pressure or vacuum in the Evaporative Emission (EVAP) system, and the outside air pressure. The Powertrain Control Module (PCM) supplies a 5-volt reference and a low reference circuit to the FTP sensor. The FTP sensor signal circuit voltage varies depending on EVAP system pressure or vacuum. If the FTP sensor signal voltage goes above or below a calibrated value, the PCM will set a DTC. The following table illustrates the relationship between the FTP sensor signal voltage and the EVAP system pressure/vacuum. See FTP SENSOR SIGNAL VOLTAGE/EVAP SYSTEM PRESSURE/VACUUM table.
FTP SENSOR SIGNAL VOLTAGE/ EVAP SYSTEM PRESSURE/VACUUM
| FTP Sensor Signal Voltage | Fuel Tank Pressure |
|---|---|
| High, Approximately 1.5 Volts or More | Negative Pressure/Vacuum |
| Low, Approximately 1.5 Volts or Less | Positive Pressure |