Circuit Description

This diagnosis detects leaks in the EVAP purge line using engine intake manifold vacuum. If pressure does not increase, the ECM will check for leaks in the line between fuel tank and EVAP Canister Purge Volume Control Solenoid Valve (EVAP-CPVCSV), under the following "vacuum test" conditions:

• The vacuum cut valve bypass valve is opened to clear the line between the fuel tank and the EVAP-CPVCSV.
• The EVAP Canister Vent Control Valve (EVAP-CVCV) will then be closed to shut the EVAP purge line off.
• The EVAP-CPVCSV is opened to depressurize the EVAP purge line using intake manifold vacuum. After this occurs, the EVAP-CPVCSV will be closed.