Your GMC Safari may have failed the EVAP test because it was unable to hold the required amount of pressure during the EVAP test.
In order to find the fault you will need to trace the EVAP tubes between your van's engine and gas tank, and check for breaks, cracks, and leaks in-between. You also need to ensure the EVAP solenoid is functioning properly and sealing the EVAP system while it is not activated by the Engine Control Unit (ECU).
posted by SmogTips Support
