Evaporative Emissions System: Testing and Inspection

Evaporative Control Canister And Valve:

Check vacuum hoses and connections
Check vacuum hose between:
- EVAP valve and intake manifold for restrictions
- EVAP valve and canister for restrictions

Check connections at:
- Intake manifold
- EVAP canister
- EVAP valve

Check vacuum to EVAP valve
With engine idling, check for vacuum from the intake manifold to the EVAP valve. Clean or replace hose and nipple as necessary.

Check vacuum from EVAP valve
With the engine idling, check that no vacuum is present when the valve is not activated.

Wait for valve activation (usually 1 minute after starting a warm engine) and recheck for vacuum.

If valve fails either test, replace valve and recheck.

Check vacuum at EVAP canister
With engine idling and valve activated, check for vacuum at EVAP canister. If vacuum is not present, check and/or replace vacuum hose from valve to canister.

Check EVAP valve operation
Disconnect EVAP valve connector and apply 12 VDC to valve. Valve should click when voltage is applied.
- If valve does not click, check resistance.
- Resistance should be 40-60 Ohms.
- Replace valve if necessary.