Dashpot Control Vacuum Solenoid

ECU controls solenoid which regulates vacuum to outer side of idle speed dashpot based upon coolant temperature. When solenoid is energized, vacuum signal to dashpot is blocked. This causes spring pressure to slightly open throttle valve, allowing for cold fast idle. The inner side of idle speed dashpot controls throttle closure speed using spring pressure and an orificed (restricted) manifold vacuum signal. ECU controls outer side of diaphragm only.