What are the symptoms of diesel egr valve failure?

The symptoms of diesel egr valve failure are: 1, the engine is difficult to start and the acceleration is weak; 2, emissions are not up to standard; 3. The exhaust pipe of the vehicle emits black smoke; 4. Unstable idle speed or idling flameout; 5. The fault light flashes; 6. Engine oil burns. The reasons for the failure of egr valve of diesel engine are: 1, the quality problem of exhaust gas recirculation system itself; 2. Improper maintenance; 3. The quality of oil; 4, waste gas valve aging. Egr valve of diesel engine is a mechatronics product installed on diesel engine, which is used to control the amount of exhaust gas recirculation fed back to the intake system. It is located on the right side of the intake manifold, near the throttle body.