Diagnostic Aids

WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

An EVAP purge solenoid or EVAP vent solenoid circuit fault may have caused this DTC to set.
ECM uses the FTP sensor to detect the amount of vacuum pulled on the EVAP system during the leak diagnostic tests. Ensure that the fuel pressure sensor is not skewed by verifying the FTP sensor on the scan tool is 1.30-1.70 volts with the ignition on and fuel cap removed.
Locate the small leak with the Evaporative Emission System Tester.
The following are possible causes of a small leak: The fuel cap is leaking. The EVAP vent solenoid valve is not seating correctly. The EVAP vent hose is loose or damaged. The EVAP canister is leaking. The fuel sender assembly "O" ring is leaking. The fuel tank or filler neck is leaking.
The small leak diagnostic can detect a leak greater than 0.020" (.51 m) in diameter.
A condition may exist where a leak in the EVAP system only exists under a vacuum condition. By using the scan tool Purge/Seal function to create a vacuum, seal the system and observe the FTP parameter for vacuum decay, this type of leak may be detected.