Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2003 GMC Yukon XL, 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Suburban, and 2003 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

To help locate intermittent leaks, use the J 41413-200 Evaporative Emissions System Tester (EEST) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the J 41413-SPT High Intensity White Light. Introducing smoke in 15 second intervals will allow less pressure into the EVAP system. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
A temporary blockage in the EVAP purge solenoid purge pipe or EVAP canister could cause an intermittent condition. Inspect and repair intermittent condition. Inspect and repair any restriction in the EVAP system.
To improve visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT.
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.
If the condition is intermittent, see INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM.