Diagnostic Aids

WARNING: This page is about a different car, the 2002 Pontiac Sunfire, 2002 Pontiac Grand Am, 2002 Oldsmobile Alero, and 2002 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.

Reviewing failure records vehicle mileage since diagnostic test last failed may help determine how often condition that caused DTC to set occurs. This may assist in diagnosing condition.
Use EVAP pressure/purge diagnostic station to pressurize EVAP system to aid in locating intermittent leaks. Move all EVAP components while testing with Ultrasonic Leak Detector.
A temporary blockage in EVAP canister purge valve, purge pipe or EVAP canister could cause an intermittent condition.