Air Injection: Testing and Inspection

1. Remove air cleaner cover and filter.
2. Start engine and check for air suction (bubbling noise) from air cleaner port with engine idling. System should operate and noise should be heard.
3. If system is not operating at idle, disconnect vacuum hose from air suction valve and check for vacuum.
4. If vacuum is present, replace air suction valve. If no vacuum is present, proceed as follows:
a. Check for vacuum at air suction control solenoid valve. If no vacuum is available to valve, trace vacuum hoses and repair as needed.
b. If vacuum is available to air suction valve, check for voltage across valve terminals.
c. If voltage is available, replace solenoid valve. If no voltage is available, check continuity of system wiring, test sensors and repair or replace as needed. If sensors and wiring are satisfactory, replace control unit and retest system.
5. Raise engine speed above 2000 RPM and check for air suction at air cleaner port. No noise should be heard.
6. If air suction system operates above 2000 RPM, check for vacuum at air suction control valve.
7. If no vacuum is available, replace air suction valve. If vacuum is present at air suction valve above 2000 RPM, proceed as follows:
a. Check for voltage at air suction control valve solenoid with engine running above 2000 RPM.
b. If no voltage is present, replace solenoid. If voltage is present, check for incorrect sensor inputs or defective control unit.