System Test
- With filler cap removed, disconnect evaporative hose between carbon canister and fuel tank. Blow air toward carbon canister. No resistance should be felt. Blow air toward fuel tank. Slight resistance should be felt because of the 2-way valve.
- Disconnect vacuum hose from pipe going to carbon canister vacuum vent port. Blow air into hose. If air can be blown into canister, the diaphragm in purge control valve is ruptured and canister must be replaced.
- Blow air into all other pot's on the carbon canister. If air does not pass easily through all other hoses, replace canister.
Courtesy of SUBARU OF AMERICA, INC.