Auxiliary Air Valve

Warm engine to temperature of about 68°F (20°C) and stop engine. Disconnect air hoses and electrical connector from valve. Visually check that diaphragm is partially open. Connect battery power to valve terminals. After 8 minutes, diaphragm should be completely closed.
If not, check internal resistance of valve with an ohmmeter connected to both terminals. Resistance should be 40 ohms on turbocharged models, and 46 ohms on all others. If valve does not respond as outlined, replace auxiliary air valve.