Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 11 other vehicles, including the 2002 GMC Yukon XL, 2002 GMC Yukon, 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, and 2002 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.

Use the J 41413 EVAP Pressure/Purge Diagnostic Station in order to pressurize the EVAP system to aid in locating intermittent leaks.
Move all EVAP components while testing with the J 41416 Ultrasonic Leak Detector.
A temporary blockage in the EVAP canister purge valve, purge pipe, or EVAP canister could cause an intermittent condition. To repair a blockage in the EVAP system, See EVAPORATIVE EMISSION SYSTEM CLEANING in REMOVAL, OVERHAUL & INSTALLATION.