1.6L 4A-FE

Install tachometer. With engine coolant less than 176°F (80°C), remove air intake hose from throttle body.
Start engine. Place finger over air valve port to block airflow. See Fig 1. Engine speed should decrease noticeably.
Allow engine to warm to normal operating temperature. Place finger over air valve port to block airflow. Engine speed should not decrease more than 50 RPM.
If engine RPM does not respond as indicated, check for vacuum leaks after the valve or restricted chamber in auxiliary air valve circuit. If no defects are found, replace auxiliary air valve.

Fig 1: Checking Auxiliary Air Valve (1.6L 4A-FE)