Evaporative Emissions System: Testing and Inspection

CHECKING THE EVAPORATIVE EMISSION SYSTEM





Checking the Evaporative Emission Valve
^ Disconnect the ventilation hose and the canister control from the Throttle Body.
^ Connect a vacuum pump to the ventilation hose (the thick hose) and pump out air.
^ When pumping a partial vacuum should be displayed on the meter.
^ The pressure quickly returns to atmospheric pressure. However there is a noticeable resistance to pumping.

If partial vacuum and resistance are OK:
- Check vacuum hose.
If partial vacuum or resistance are not obtained:
- Check the ventilation hose to the canister for damage or leaks.
If the ventilation hose is OK:
- Try using a new canister.





Checking the Vacuum Hose
^ Pump air out of the vacuum hose (the thin hose).
^ The meter should display a partial vacuum.

If a partial vacuum is obtained:
- Check the canister control.
If no partial vacuum is obtained:
- Check the vacuum hose for damage or leaks.
If the vacuum hose is OK:
- Try using a new canister.





Checking the Canister Control
^ Release the vacuum.
^ Blow into the ventilation hose (the thick hose).

The hose should be airtight.

If the ventilation hose is not airtight:
- Check the hose for damage.
If the hose is OK:
- Pump air out of the thin hose.
- Blow into the ventilation hose again.
- It should be possible to blow through the canister valve with only a light resistance.
If the valve is OK:
- The canister and canister control are OK.
- Return to fault tracing where it was interrupted.
If the valve is sealed.
- Try using a new canister.