Diagnostic Aids
- A condition may exist where a leak in the EVAP system exists only under a vacuum condition. Test for this condition by using a scan tool Purge/Seal function to create a vacuum, then observe the FTP parameter for a vacuum decay.
- To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT High Intensity White Light. See Special Tools .
- To help locate intermittent leaks, use the J 41413-200 Evaporative Emissions System Tester (EEST) 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.
- Observe the Freeze Frame/Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition occurs that caused the DTC to set. This may assist in diagnosing the condition.