What to Do If Failing the Annual Vehicle Inspection Due to Emission Standards?
3 Answers
There are many reasons for failing the vehicle emission inspection. Below is a detailed analysis of specific reasons for failing the annual emission inspection: 1. Excessive levels of CO, HC, and NO: This indicates a malfunction in the vehicle's catalytic converter and oxygen sensor. In this case, the catalytic converter and oxygen sensor should be cleaned, and if necessary, replaced directly. 2. Only CO and HC levels are excessive: This usually indicates a problem with the vehicle's intake system, along with carbon buildup in the cylinders. In this situation, the engine carbon deposits and the vehicle's intake system should be cleaned promptly. 3. Only CO level is excessive: This is generally caused by incomplete combustion of fuel and air mixture in the engine cylinders. In this case, the air filter and spark plugs should be checked and cleaned promptly, and if necessary, replaced directly. 4. CO and HC levels are excessive: And the vehicle emits a large amount of black smoke when starting. This is usually caused by severe wear of the engine cylinders, requiring replacement of components such as piston rings and cylinder heads.
Last year, I encountered an issue with failing the environmental protection inspection due to excessive emissions, which was quite a headache at the time. But now I have some experience. Excessive emissions are mostly caused by a failed catalytic converter or faulty oxygen sensor, or it could be due to aging spark plugs leading to incomplete combustion. It's essential to get a professional inspection first to confirm the specific cause—don't just guess. If the catalytic converter is broken, it needs to be replaced. An aftermarket part can cost around 2,000 yuan, and make sure to get a warranty from the repair shop. Pay attention to your driving habits—avoid always filling up with cheap gas. Using higher-grade fuel from reputable gas stations can reduce carbon buildup. If your car is over ten years old, it might be easier to hire an agent (commonly referred to as a 'yellow bull' in China) to handle the inspection for you. Spending around 400–500 yuan can save you a lot of hassle, as they have connections to help you pass. Regular maintenance, such as cleaning the throttle body and fuel injectors, is crucial to avoid failing the inspection again next time.
My old car failed the emissions test during last year's inspection, and it took a long time to figure out the issue was with the ignition system. You can start by checking the spark plugs and high-voltage wires—excessive gaps or leakage can affect combustion efficiency. Then inspect if the air filter is clogged; a dirty one can lead to insufficient air intake and increased emissions. Remember to warm up the car before the test, as cold engines usually produce worse emission data. A drop in catalytic converter efficiency is also a common issue—repair shops have equipment to measure its temperature, and if it's abnormal, it might need replacement. I suggest starting preparations two months in advance: add a bottle of fuel system cleaner with each refueling to clean the fuel lines, and rev the engine at high speeds on the highway to clear carbon deposits. If repairs don’t work after several attempts, consider trading it in for a new one—there are substantial subsidies for new energy vehicles now.
