TESTING

1. Pinch the hose connecting the air intake duct and the auxiliary air valve, then note engine rpm change. With the engine cold, engine idle speed drops as the hose is pinched. With the engine hot, reduction in engine rpm is within 100.
2. When the engine is started, the auxiliary air valve is heated by the built-in heater and its shutter valve gradually closes. This causes engine rpm to lower gradually until the specified idling rpm is reached. If the engine speed does not drop to the idling rpm smoothly, the heater circuit or the heater power supply circuit may be faulty. Proceed as follows:
   1. Disconnect the auxiliary air valve electrical connector.
   2. Using an ohmmeter, measure the resistance between the 2 terminals on the auxiliary air valve. Ohmmeter should read other than 0 ohms and infinity.
   3. If ohmmeter reads 0 ohms or infinity, replace the auxiliary air valve.
   4. Disconnect the auxiliary air valve electrical connector.
   5. Using a voltmeter, check the voltage on the auxiliary air valve connector.
   6. With the engine running, voltmeter should read 12 volts or more. If specifications are not within parameters, check the harness and connector for faults.