Evaporative Emissions System: Testing and Inspection

Prior to inspection, ensure check engine light exhibits code 12 and all sensors operating properly and engine is at normal operating temperature.
1. Support vehicle so rear wheels rotate freely.
2. Set transmission in neutral or park range and transfer in 2H.
3. Start engine, then release parking brake and ensure rear wheels are turning. If not, perform following check with one rear tire locked and the other turned by hand.
4. Disconnect purge hose from canister, then place finger over end of disconnected hose and ensure vacuum is not felt while engine is running at idle speed and that vacuum is felt when engine speed is increased to higher than 1500 RPM.
5. If results are not as specified, check vacuum passage, hoses, VSV, wire harness and ECM.