Land Cruiser, RAV4, Sienna, Tacoma, Tundra & 4Runner

EVAP system prevents fuel tank gasoline vapors from escaping into the atmosphere. Fuel tank gasoline vapors are routed through EVAP canister into air cleaner and intake manifold for combustion in the cylinders. Vapor pressure sensor and vapor pressure sensor Vacuum Switching Valve (VSV) are used to determine if a leak or an abnormality exists in EVAP system. See Figure. Engine Control Module (ECM) determines if a leak or an abnormality exists in EVAP system by using input signal from vapor pressure sensor. Vapor pressure sensor may also referred to as EVAP vapor pressure sensor. Vapor pressure sensor VSV may also be referred to as EVAP Vapor Pressure Sensor Vacuum Switching Valve (EVAP-VPSVSV). If a leak or an abnormality exists in EVAP system, a Diagnostic Trouble Code (DTC) will be stored in ECM. See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article for retrieving and servicing of DTCs. An EVAP Vacuum Switching Valve (VSV) is used to control EVAP system. ECM operates EVAP VSV which controls vacuum flow for EVAP operation. For EVAP system and component testing, see appropriate SYSTEM & COMPONENT TESTING article.