Diagnostic Aids
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2003 Pontiac Grand Prix, 2003 Pontiac Bonneville, 2003 Chevrolet Monte Carlo, 2003 Chevrolet Impala, and 2003 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
To help locate intermittent leaks, use EVAP Pressure and Purge Station (J 41413) to pressurize EVAP system. Move all EVAP components while testing with Ultrasonic Leak Detector (J 41416).