What to Do If Your Car Fails the Environmental Protection Test?
2 Answers
If your vehicle fails the environmental protection test three times, the first consideration should be whether there is an issue with the catalytic converter. Car exhaust contains many pollutants, with the primary ones being carbon monoxide, hydrocarbons, and nitrogen oxides. Under normal circumstances, the catalytic converter processes these through oxidation and reduction, converting them into harmless carbon dioxide, nitrogen, and water, thereby achieving purification. The catalytic converter is called a "three-way" catalytic converter because it contains three precious metals: platinum (Pt), rhodium (Rh), and palladium (Pd), hence the name "three-way." Solution: Before the test, drive on the highway for a while to allow the catalytic converter to reach its optimal operating temperature before testing. The most important point is not to turn off the engine before the test, as this keeps the catalytic converter at a certain temperature. If this still doesn't work, directly clean the catalytic converter and then retest to see if it passes. If it still fails, consider the following possible reasons: 1. The oxygen sensor is faulty. Solution: Replace the oxygen sensor. 2. The air filter is problematic. Solution: Replace the air filter. 3. The fuel is the issue. Solution: Add half a tank of E10 ethanol gasoline. Ethanol has a high oxygen content, which aids combustion. If none of these methods work, there is basically no other solution.
Failing the car's environmental protection test is quite a headache, and I've been through it a few times before. It's usually caused by excessive emissions, possibly due to a clogged or aged catalytic converter, leading to poor exhaust treatment. I suggest checking the air filter and oxygen sensor first to see if the filter is too dirty or the sensor is malfunctioning. If it's an easy fix, clean them and try the test again. If that doesn’t work, take a high-speed drive to burn off carbon deposits—it might just pass. If the problem persists, visit a professional repair shop. They can thoroughly inspect the engine and exhaust system, and replacing a new part might only cost a few hundred bucks. Remember not to slack on regular maintenance; changing the oil and spark plugs periodically can reduce such issues. My experience is that addressing problems promptly saves both hassle and money, while delaying might lead to fines or affect the annual inspection.
