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.
If DTC P0440, P0442, P0446 or P0455 is set, EVAP special functions on the scan tool will not be allowed. Clear DTC(s) before performing these tests.
The ECM uses the fuel tank pressure sensor to detect the vapor in the fuel tank during all parts of the EVAP diagnostic system test. Make sure the fuel tank pressure sensor is not skewed by verifying fuel tank pressure sensor on scan tool is 1.4-1.6 volts with ignition on and engine off.
Possible causes of a blocked EVAP vent system:
- EVAP vent solenoid blocked or stuck valve.
- EVAP vent foam filter for a blocked condition (filter can be checked by removing EVAP canister end cover near EVAP vent solenoid).
- EVAP vent hose from EVAP canister to fuel filler neck kinked or pinched.
- EVAP canister restricted.
- If an EVAP diagnostic test is aborted due to changing enabled criteria, the ECM will run the entire EVAP test up to 3 times per ignition cycle.