EVAP Valve Check
- Disconnect ventilation hose and canister guide from throttle body. Connect vacuum pump to ventilation (large) port and begin pumping to obtain partial vacuum. See Fig 1
. Even though pressure returns quickly to atmosphere pressure, resistance should be felt when pumping. If vacuum and resistance are okay, go next step. If vacuum cannot be reached or resistance is not okay, check ventilation hose connected to canister for damage or leakage. If hose is okay, repeat test using new canister.
Courtesy of VOLVO CARS OF NORTH AMERICA.
- Apply vacuum to small vacuum port. If partial vacuum is present, go to next step. If no partial vacuum is present, check vacuum hose connected to canister for leakage. If hose is okay, repeat test using new canister.
- Maintain vacuum in vacuum hose. Blow into hose that fits into large port. If air passes through canister with slight resistance, canister and guide are okay. If air does not pass through canister, check vacuum hose for blockage. If vacuum hose is okay, repeat test using new canister.