Fuel Tank Pressure (Ftp) Sensor

The FTP Sensor is located on the Recirculation Tube. It measures the pressure in the Evaporative Emissions System and converts it into a voltage. The PCM uses the FTP Sensor for the purge system performance diagnostics (P0441).  The Sensor is used in the following manner:

• When the Purge Solenoid is actuated and the PCM monitors the change in the FTP Sensor reading over time. The PCM expects to see the pressure/vacuum reading decrease more than a calibrated threshold.
• When the Purge Solenoid is then deactivated and the PCM monitors the change again over time. The PCM expects to see the pressure reading increase more than a calibrated threshold over a period of time.