Idle Speed Air Control Valve

With ignition switched off, idle speed air control valve is opened to maximum by a set of return springs. This is the same position as that of "limp-home" engine operation. With ignition on and engine off, idle speed air control valve is activated. This provides a valve opening which is determined by coolant temperature.

ECU supplies specific voltage to air control valve which determines correct opening for setting engine speed. A/C operation will also send a signal to the ECU which will modify the signal to the air control valve. Engine speed is controlled by temperature from 1000 RPM at 0°F (-20°C) to low of 720 RPM at 68°F (20°C).