Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2011 GMC Yukon XL, 2011 GMC Yukon, 2011 Chevrolet Tahoe, 2011 Chevrolet Suburban, and 2011 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

The EVAP system can be filled with smoke more quickly and completely by opening the system opposite the end where the smoke is injected. When injecting smoke at the service port remove the fuel fill cap, or temporarily leave the vent open, until smoke is observed then close the system and continue testing. If using a fuel cap adapter at the filler neck, use the J-41413-VLV service port vent tool at the service port to allow the system to fill faster.
To help locate intermittent leaks using the J-41413-200 evaporative emissions system tester , move all EVAP components while observing smoke with the GE-41413-SPT high intensity white light.
Individual components can be isolated and tested using adapters in the J-41413-300 cap and plug kit.
Do not disturb any of the fuel system components after verification of a DTC P0442 on the vehicle.
Close the EVAP canister vent valve with a scan tool to seal the EVAP system and monitor FTP sensor in mm Hg for approximately two minutes. If vacuum is present remove the purge solenoid valve and test with J 41413-200. Add smoke on the fuel tank side of the purge solenoid and allow pressure to stabilize for 2 minutes then observe for leaks.
A condition may exist where a leak in the EVAP system only exists under a vacuum condition. This type of leak may be detected by using the scan tool Purge/Seal function to create a vacuum in the EVAP system and then observe the FTP parameter for vacuum decay.