What to Do If the Vehicle Fails the Environmental Protection Inspection?

[VonLilah]

Solutions for failing the environmental protection inspection are as follows: 1. If CO, HC, and NO are all exceeding the standards, it indicates a malfunction in the vehicle's three-way catalytic converter and oxygen sensor. In this case, the three-way catalytic converter and oxygen sensor should be cleaned, and replacement may be necessary if required. 2. If only CO and HC exceed the standards, it is generally due to a fault in the vehicle's intake system, along with carbon buildup in the cylinders. In this situation, it is essential to clean the engine carbon deposits and the vehicle's intake system promptly. 3. If only CO exceeds the standard, it is usually caused by incomplete combustion of fuel and the air-fuel mixture in the engine cylinders. In this case, check the air filter and spark plugs, clean them in time, and replace them if necessary. 4. If CO and HC exceed the standards, and the vehicle emits a large amount of black smoke upon starting: This is typically caused by severe wear of the engine cylinders, requiring the replacement of components such as piston rings and cylinder heads.