Idle Speed/Throttle Actuator - Mechanical: Testing and Inspection

Fig. 27 Troubleshooting Flow Chart. Testing A/C Idle Boost Solenoid Valve:

1. Start engine and warm to normal operating temperature.
2. Check idle speed with headlights, heater blower, rear window defogger, cooling fan and A/C off. Idle speed should be 750-850 RPM on manual transmission and 700-800 RPM on automatic transmission in N or P.
3. If idle speed is within specifications, proceed to step 7.
4. If idle speed is not within specifications, disconnect vacuum hose from idle boost throttle controller and check vacuum. There should be no vacuum.
5. If there is no vacuum, check throttle valve shaft for binding or sticking and replace idle boost throttle controller.
6. If there is vacuum, refer to Fig. 27.
7. If idle speed is within specifications in step 2, check idle speed with A/C on.
8. If idle speed is not 750-850 RPM on manual transmission, or not 700-800 RPM on automatic transmission in N or P, disconnect vacuum hose from idle boost throttle controller and check for vacuum. There should be vacuum.
9. If there is vacuum, check throttle valve shaft for binding or sticking and replace idle boost throttle controller.
10. If there is vacuum, refer to Fig. 27.