Circuit Description

The ECM changes duty signal to EVAP Vacuum Switching Valve (VSV) so that intake quantity of HC emissions is appropriate for driving conditions (engine load, engine speed, etc.) after engine is at normal operating temperature. DTC is set when proper response to computer command does not occur. Possible causes are:

• VSV open or short circuit.
• EVAP VSV.
• ECM.
• Vacuum hose blocked or disconnected.
• Charcoal canister.