Auxiliary Air Valve

Disconnect air cleaner hose from throttle body. Start engine. Check that there is air continuity at auxiliary air valve port under following conditions. Perform check, following procedures given in step 2).
When cooling water temperature is bellow 137°F (75°C), apply finger to auxiliary air valve port. Ensure that engine speed drops. When coolant temperature is above 146°F (80°C), apply finger to auxiliary air valve port. Ensure that engine speed does not change. If auxiliary air valve exhibits any malfunction, replace throttle body.

Fig 1: Cross-Sectional View of Auxiliary Air Valve

Courtesy of DAIHATSU MOTOR CO.,LTD.