What to Do If Vehicle Fails Emission Test?
3 Answers
There are mainly two reasons why a vehicle's emissions fail to meet standards: 1. Poisoned Catalytic Converter: This occurs due to high sulfur content in gasoline or the use of sulfur-phosphorus antioxidant in lubricants. The gasoline and lubricants should be replaced promptly. 2. Catalytic Converter Failure: Catalytic converter failures are categorized into reversible and irreversible failures. Reversible failure happens when the catalytic converter is used beyond its service life, leading to high-temperature deactivation of the catalyst. Irreversible failure is caused by sintering or damage to the catalytic converter. Additional Information: Composition of Vehicle Emissions: The main components of vehicle emissions include carbon monoxide, hydrocarbons, nitrogen oxides, carbon dioxide, sulfur dioxide, lead compounds, and some particulate matter.
My previous car failed the emissions test, with common causes being a aging catalytic converter, faulty oxygen sensor, or spark plug carbon buildup. That time I drove it to the repair shop, and after inspection, they found the catalytic converter was clogged. It passed the test after replacement. I recommend starting with simple steps first: check if any warning lights are illuminated on the dashboard, try replacing the air filter yourself—if it's clogged, it can affect the air-fuel mixture; and use a cleaning fuel additive to help purify the fuel system. Don’t neglect regular maintenance—changing the oil on time and maintaining the engine can reduce emissions at the source, saving money and peace of mind. Experience tells me that addressing emission issues early avoids bigger expenses.
I'm a car enthusiast and often fix exhaust issues myself. First, I use an OBD2 scanner to read trouble codes, like P0420 which usually indicates a catalytic converter or sensor problem. I clean or replace spark plugs to ensure proper ignition; a dirty air filter directly affects emissions, and replacing it is simple. When the oxygen sensor gets dirty, I clean it with a specialized spray. A faulty catalytic converter requires professional repair, but regular use of fuel system cleaners can prevent issues. Handling these small tasks makes passing emissions tests easy while also learning about cars.
