Component Tests and General Diagnostics

Fig. 12 Component locations:

AIR SWITCHING VALVE

1. Run the engine at idle.
2. Disconnect the solenoid valve connector to turn off the solenoid valve. (Manifold vacuum will act on the air switching valve, causing the valve to open.) If the idle speed falls excessively or the engine stalls, the air switching valve and solenoid valve are operating properly. If the speed does not change, check the vacuum passage for clogging and check the condition of air switching valve or solenoid valve.
3. With the engine at idle, battery voltage should be present at the solenoid valve connector. If no voltage is present, the electrical wiring or engine speed sensor is defective.
4. Increase the engine speed to 1,500 rpm. Verify that voltage is present at the solenoid valve connector. If there is no voltge, the engine speed sensor is defective.
5. Increase the engine speed to 2,500 rpm. Verify that no voltage is present at the solenoid valve connector. If there is voltage, the engine speed sensor is defective.