Es300, LS400, RX300, SC300 & SC400

The EVAP system prevents fuel tank gasoline vapors from escaping into the atmosphere. Fuel tank gasoline vapors are routed through EVAP canister into intake manifold for combustion in the cylinders.

The Engine Control Module (ECM) monitors fuel tank pressure to determine if a leak or an abnormality exists in the EVAP system. A pressure switching valve Vacuum Switching Valve (VSV) is located in vapor line to the EVAP canister. The ECM will operate the pressure switching valve VSV, allowing vapor pressure sensor to monitor the fuel tank pressure and EVAP system. Vapor pressure sensor delivers an input signal to ECM to indicate fuel tank pressure. If a leak or an abnormality exists in the EVAP system, a diagnostic trouble code will be stored in the ECM.

An EVAP Vacuum Switching Valve (VSV) is used to control EVAP system. The ECM operates EVAP VSV which controls the vacuum flow for EVAP operation. For EVAP system testing and component locations, see EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article.