Evaporative Emissions System: Testing and Inspection
EVAPORATIVE EMISSION SYSTEM LEAK TESTSpecial Tool(s):
Special Tool(s)
Phase 1 - Leak Verification
1. Using the scan tool, run the evaporative emissions (EVAP) system test.
2. NOTE: Some small leaks may not be detected using the EVAP system test. If the system has passed the test but a leak is still suspected, proceed to Phase 2.
If the EVAP system failed the EVAP system test, proceed to Phase 2.
Phase 2 - System Leak Check
1. Disconnect the upper fuel vapor tube quick connect coupling from the EVAP canister purge valve.
2. Connect the smoke machine emissions tester to the upper EVAP canister purge valve fitting.
3. NOTE: In the scan tool, the EVAP canister purge valve is referred to as the EVMV.
Using the scan tool, energize the EVAP canister purge valve to the open position.
4. CAUTION: The canister vent solenoid must not be energized for more than 9 minutes at one time. Once the canister vent solenoid is energized and de-energized, adequate time must be allowed for the component to cool adequately. Failure to allow the component to cool may create a false failure in the diagnostics, causing unnecessary repairs.
Using the scan tool, close the canister vent solenoid.
5. Introduce smoke from the smoke machine emissions tester into the EVAP system.
6. Use the halogen light provided with the smoke machine emissions tester to look for smoke coming from the EVAP system. This will indicate a leak point.
7. Repair any leaks as necessary.
8. Repeat the leak test until the system passes.