Q: What is the general description of the EGR system and EGR Valve on Toyota Solara?
A: To reduce oxides of nitrogen (NOx) emissions, some exhaust gases are recirculated through the EGR valve to the intake manifold, which lowers combustion temperatures. The EGR system includes an EGR valve, an EGR modulator, a vacuum switching valve (VSV), and vacuum lines to the throttle body, with the EGR valve's position controlled by vacuum managed by the Powertrain Control Module (PCM). For EGR valve replacement, first remove the throttle body, detach the vacuum hose from the EGR valve, disconnect the EGR pipe, and take out the mounting bolts to remove the valve from the intake manifold, checking for sticking or heavy carbon deposits; if necessary, clean or replace the valve and use new gaskets during installation. For the EGR vacuum modulator, label and disconnect the vacuum hoses, then remove the modulator from its bracket; if reusing, check and clean the filters with compressed air, ensuring proper orientation upon reinstallation, or replace them if cleaning is not possible. For the vacuum switching valve, disconnect the negative battery cable, raise the vehicle securely, locate the VSV near the exhaust manifold, unplug the electrical connector, label and disconnect the vacuum hoses, and remove the VSV from its mounting bracket, separating it if needed; installation follows the reverse order of removal.