Exhaust Gas Recirculation: Testing and Inspection

1. Check vacuum hose routing. If hose is improperly connected, clogged or leaking, repair or replace as necessary.
2. Warm engine to normal operating temperature and run at idle.
3. Disconnect vacuum hose from top of EGR control valve and plug hose. If engine roughens, check EGR control valve.
4. Connect suitable vacuum gage to EGR control valve and ensure gage shows no vacuum.
5. Increase engine speed to 2500 RPM and ensure gage shows vacuum.
6. If vacuum is not as described, check duty solenoid valve and terminals 2M and 2N of EGI control unit.
7. Using tee fitting, connect suitable vacuum gage between duty solenoid valve and EGR control valve.
8. Accelerate engine and note amount of vacuum.
9. Disconnect vacuum hose at top of EGR control valve, then accelerate engine and note amount of vacuum.
10. If vacuum in step 9 is not greater than that in step 8, check EGR position sensor, 2F terminal of EGI control unit and the duty solenoid valve.
11. Plug disconnected vacuum hose and disconnect electrical connector at water temperature switch.
12. Increase engine speed to 2500 RPM. If gage shows vacuum, check duty solenoid valve and the 1H terminal of EGI control unit.