Diagnostic Aids

WARNING: This page is about a different car, the 2002 Pontiac Firebird and 2002 Chevrolet Camaro. However, it is still accessible from the selected car via links, so may be relevant.

Use the EVAP Pressure/Purge Diagnostic Station (J 41413) in order to pressurize the EVAP system to aid in locating intermittent leaks. Move all EVAP components while testing with the Ultrasonic Leak Detector (J 41416).
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 appropriate REMOVAL, OVERHAUL & INSTALLATION article.
Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.