Circuit/System Testing
- Verify the following conditions are not present:
- Incorrect EGR Valve for engine application
- A vacuum leak between the EGR valve and the intake manifold
- Signs of external leakage usually indicated by carbon buildup around the mating surfaces of the components or an audible exhaust noise
- Restrictions in the passages or EGR valve caused by carbon deposits or casting flash
- MAP sensor for being shifted, stuck, skewed, and for correct vacuum supply. Refer to Manifold Absolute Pressure Sensor Diagnosis .
- Leaking, restricted, or modified exhaust system
- Mechanical failure in the engine such as worn piston rings, camshaft, or incorrect timing components installation-Refer to Symptoms - Engine Mechanical .
IMPORTANT: Restrictions can cause excessive back pressure and low engine vacuum - If all conditions test normal, replace the EGR valve.