Common Reasons Your Exhaust Problems Can Fail Your Emissions Test

exhaust problems

Emissions tests are conducted to check for any pollutant emissions that might be escaping from the engine of a vehicle. Your car must meet a list of standards to pass an emissions test. What are the reasons your car’s missing the mark?

Three Common Causes for Failed Emissions Tests

1. Faulty oxygen sensor
If your car’s oxygen sensor is faulty, it can’t properly measure the amount of oxygen that is in the exhaust gas. A defective oxygen sensor can lead to other more serious problems, including overheating of your car, high toxic emissions, and the loss of accelerated power.

2. Defective ignition system
If hydrocarbons were detected during your emissions test, the problem can most likely be traced to your ignition system. A defective ignition system is often caused by poor maintenance, which can seriously affect your vehicle’s distributor cap, spark plugs, and ignition timing.

3. Air injection system malfunction
Your car contains an Evaporative Emission Control System, which prevents fuel vapors from the fuel system and tank from escaping into the atmosphere. Leaks in the vacuum hoses, defective valves, or a faulty gas cap can cause your air injection system to malfunction.