Evaporative Emissions System: Testing and Inspection

NOTE: Troubleshoot with the Self-Diagnosis Checker before performing the following steps. Check the condition of the wiring harness and/or vacuum lines and connectors before checking the sensors or switches.

1. Check the vacuum hose routing.
2. If a poor connection, clog, or leak is found, repair or replace the necessary part.
3. Warm up the engine and run it at idle.

Checking Vacuum From Hose "A":

4. Disconnect vacuum hose "A" from the No. 1 purge control valve, and connect a vacuum gauge to the disconnected hose.
5. Increase the engine speed to 2,500 rpm and verify that the gauge shows more than 150 mmHg (5.9 in.Hg) vacuum.
6. If it does not, check the water thermovalve.
7. Reconnect hose "A" to the No. 1 purge control valve.

Checking Vacuum From Hose "B":

8. Disconnect vacuum hose "B" from the canister, and connect a vacuum gauge to the disconnected hose.
9. Verify that there is vacuum when the engine speed exceeds 1,400 rpm.
10. If no vacuum is evident, check the purge solenoid valve, No. 3 purge control valve, and the 1V terminal of the engine control unit.
11. Reconnect hose "B" to the canister.

Checking Evaporation Pipe:

12. Disconnect the evaporation hose from the evaporation pipe.
13. Connect a vacuum pump to the evaporation pipe.
14. Operate the vacuum pump and verify that no vacuum is held.
15. If it is, check the check-and-cut valve and evaporation pipe for clogging,