Evaporative Emissions System: Testing and Inspection

NOTE: Before inspection, check to make sure that gear shift lever is in neutral position (with A/T model, selector lever in "P" range) and that parking brake lever is pulled all the way up.




1. Disconnect purge hose from pipe in engine room.
2. Place finger against the end of disconnected hose and check that vacuum is not felt there when engine is cool and running at idle speed.
3. Connect purge hose to pipe and warm up engine to normal operating temperature.
4. Disconnect purge hose from pipe.
5. Also check that vacuum is felt when engine is running at idle speed.

NOTE: The EVAP canister purge system does not perform purging (vacuum is not detected at the purge hose) unless the engine is sufficiently warmed up and the heated oxygen sensor is activated fully. Also, when the purge hose is disconnected in Step 4), the air is drawn into the purge line. As a result, ECM detects a change in the purge gas concentration and sometimes stops purging but this indicates nothing abnormal.

If check result is not satisfactory, check vacuum passage, hoses, EVAP canister purge valve, wire harness and ECM.