Fuel Tank Leak Test: Description
WARNING: This page is about a different car, the 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
The fuel tank leak test is used to locate any fuel or fuel vapor escaping the fuel tank area. Fuel vapors escaping above the fuel level will be detected when the EVAP leak diagnostic completes one test cycle. The MIL will illuminate after the EVAP leak diagnostic completes two test cycles for a large leak or up to eight test cycles for a small leak, only when a condition is detected.