The Aux air valve allows air to by-pass the throttle when the engine is warming up to permit a higher idle speed. The valve consists of an electrically heated bimetal valve. When the engine is first started the valve will be open, as the engine runs the bimetal valve is heated which slowly closes off the aux air by-pass. This reduces the ammount of air entering the engine and reduces the idle speed.

A simple test to see if the valve is workingis remove it from the car and put it in the freezer for 15min. When removed the valve should be open, if it is reinstall it back on the car and run it for 5min. The valve should now be closed.

Its located on the back lower side of the inlet manifold (near the dipstick). A black pipe runs from the throttle body round to the valve then another pipe runs from the valve to the bottom of the inlet manifold.