Exhaust Gas Recirculation: Testing and Inspection

NOTE: Before inspecting EGR system, be sure to confirm the following:
- Altitude is 3,870 ft, 1,180 m above sea level or lower and atmospheric pressure is 660 mmHg or higher.
- WTS and TPS are in good condition.
- If even one of the above conditions do not apply, EGR valve does not operate.
- Before inspection, check to make sure that gear shift lever is in neutral position and that parking brake lever is pulled all the way up.

SYSTEM INSPECTION
CAUTION: If EGR valve is hot, it may be necessary to wear gloves to avoid burning fingers.

Checking EGR Valve Diaphragm:

- When engine is cool (cooling water temperature is below 53°C, 127°F), start engine and race it, and check that EGR valve diaphragm is not operating in this state, by touching diaphragm with finger.

Checking EGR Valve Diaphragm Movement:

- Warm up engine to normal operating temperature and race it after warming up. Then check to be sure that diaphragm moves toward 1 during acceleration and toward 2 during deceleration.
- If EGR valve fails to operate properly, check vacuum hoses EGR valve, EGR modulator, VSV, wire harness and ECM.
- Keep engine running at idle speed and open EGR valve by hand, and engine should either stop or reduce its speed. If neither occurs, EGR passage is clogged. Clean it.