Diagnostic Aids

WARNING: This page is about a different car, the 2010 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.

A loose, missing, incorrect, or damaged fuel fill cap may cause this DTC to set.
To help locate intermittent leaks, use the J 41413-200 to introduce smoke into the EVAP system. See Special Tools . Move all EVAP components while observing smoke with the J 41413-SPT . See Special Tools . Introducing smoke in 15-second intervals will allow less pressure into the EVAP system. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT . See Special Tools .
Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
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 the vacuum decay, this type of leak may be detected.
If a small leak is difficult to find, it may be necessary to remove the EVAP components and leak test them one at a time.
The turbocharged engine is equipped with a one-way flow check valve that will prevent boost pressure from entering the purge line and the EVAP system. This check valve will also prevent flow from the J 41413-200 from the purge valve into the EVAP system. See Special Tools .