Testing

Intake air temperature should be below the set temperature of the intake air temperature switch. Switch should have continuity.
1. Disconnect air suction hose from anti-afterburn valve and plug hose.
2. Remove air cleaner cover and filter.
3. Start engine and check for bubbling noise from air suction port at idle. A bubbling noise should not be heard.
4. If a bubbling noise is not heard, proceed to step 6. If a bubbling noise is heard, check for voltage at the yellow/green wire of the air suction control solenoid valve.
5. If voltage is not present, proceed to step 6. If voltage is present, refer to Troubleshooting.
6. Disconnect vacuum hose No. 5 from the air suction cut-off diaphragm, then connect suitable vacuum gauge to the disconnected hose and check vacuum.
7. If vacuum is present, replace air suction control solenoid valve. If vacuum is not present, replace air suction cut-off diaphragm.
8. Disconnect intake air temperature switch electrical connector, then check for bubbling noise from the air suction port at idle. Ensure engine coolant temperature is below 122 degrees F on models except Calif. or 95 degrees F on Calif. models.
9. If a bubbling noise is heard, proceed to step 11. If a bubbling noise is not heard, check for voltage at the yellow/green wire of the air suction control solenoid valve.
10. If voltage is present, replace air suction control solenoid valve. If voltage is not present, refer to Troubleshooting.
11. Allow engine to reach normal operating temperature, then raise and support front of vehicle.
12. Place shift or selector lever in second or No. 2 position and accelerate above 15 mph, then release the throttle and check for a bubbling noise from the air suction port at idle. Check for bubbling noise within three minutes after releasing throttle or bubbling noise will stop automatically.
13. If a bubbling noise is heard, test is complete. If a bubbling noise is not heard, check for voltage at yellow/green wire of the air suction control solenoid valve.
14. If voltage is not present, refer to Troubleshooting. If voltage is present, disconnect vacuum hose No. 5 from air cut-off diaphragm.
15. If vacuum is not present, check for leaks or disconnected hose. If satisfactory, replace air suction control solenoid valve. If vacuum is present, replace air suction cut-off diaphragm.