What to Do If Failing Vehicle Emission Test During Annual Inspection?
2 Answers
Here are the corresponding solutions: 1. Clean or replace spark plugs. Spark plugs are the heart of the engine and also belong to consumable parts. When they age or get damaged, it leads to insufficient ignition capability, preventing complete combustion of the air-fuel mixture and resulting in excessive HC content in the exhaust. Daily maintenance of spark plugs can restore their activity through sandpaper or cleaning agents. If severely aged, replacement is necessary. 2. Clean or replace the catalytic converter and oxygen sensor. During vehicle operation, carbon deposits often form due to incomplete combustion of the engine's air-fuel mixture. These deposits can adhere to the interior of the catalytic converter and the surface of the oxygen sensor, causing blockages and leading to excessive exhaust emissions. 3. Perform a deep engine cleaning. Vehicle owners should visit a 4S shop or auto repair shop to clean the engine's carbon deposits. After thoroughly cleaning the throttle body, fuel lines, intake manifold, and fuel injectors, the engine's operating condition will improve significantly, avoiding excessive exhaust emissions caused by the poor condition of incomplete combustion of the air-fuel mixture.
Last year, my car failed the annual inspection due to excessive tailpipe emissions, so I quickly checked for the cause. First, I replaced the aging spark plugs with new ones and cleaned the catalytic converter, but the results were unsatisfactory. Later, I discovered a faulty oxygen sensor, and after repairing it, the car passed the inspection in one go. Everyone should pay attention to fuel quality—use qualified fuel and occasionally drive on highways to clear carbon deposits. Before the annual inspection, perform a self-check using diagnostic tools to read fault codes. If that doesn’t work, don’t delay—send it to a professional repair shop. Emission issues involve environmental regulations, and prolonged neglect can lead to fines and harm environmental safety. Regular maintenance can prevent such problems, such as cleaning fuel injectors every 20,000 kilometers. In short, addressing issues early is the most hassle-free approach—don’t go through the ordeal I did.
