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.
- Operate vehicle under condition of customer's concern. Under high temperature conditions fuel vapors may increase to point of EVAP canister vapor saturation. Fuel vapors would then be released into atmosphere. Once engine is running and EVAP purge is enabled, all fuel vapor release would be eliminated.
- Movement of EVAP pipes or fuel pipes may help find an intermittent condition.