System Test
- With gas 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 two-way valve.
- Disconnect the vacuum hose from the pipe going to the carbon canister vacuum vent port. Blow air into the hose. If air can be blown into the canister, the diaphragm in the purge control valve is ruptured and the canister must be replaced.
- Blow air into all other ports on the carbon canister. If air does not pass easily through all other hoses, replace canister.