Common Reasons for Smog Test Failures and How to Avoid Them

Smog tests, also referred to as emission tests, play a crucial role in environmental protection and public health. The State of California pioneered the implementation of smog tests in 1984 to address the challenges posed by poor air quality and air pollutants. The 1990 Clean Air Act Amendment by the Federal government further solidified the commitment to reducing toxic air emissions, emphasizing the importance of smog checks and other measures. This nationwide initiative led to the widespread adoption of smog tests across the United States. In case of smog test failures, vehicles may be subject to necessary repairs or upgrades to meet regulatory standards and contribute to a cleaner and healthier atmosphere.

Smog testing involves checking a vehicle’s exhaust and pollution control systems. It includes a visual inspection of the system and a check to determine the level of emissions leaving a vehicle’s tailpipe. Failing the test can be frustrating, but it is crucial for environmental protection. For your car to pass the smog test, its exhaust must be in good shape. In this blog, we will explore common reasons for smog test failures and how to avoid them.

As discussed above, the smog test has much to do with the exhaust system. A faulty exhaust will release a high concentration of greenhouse gases, leading to a failure in smog tests. Below are the main reasons for your vehicle’s smog test failures:

What Are The Reasons for Smog Test Failures?

As discussed above, the smog test has much to do with the exhaust system. A faulty exhaust will release a high concentration of greenhouse gases, leading to a failure in smog tests. Below are the main reasons for your vehicle’s smog test failures:

1.  Vehicle Needs Oil Change

This is one of the most common and significant reasons for a vehicle failing the smog test. If oil is not changed on time, it becomes contaminated with engine deposits and sludge. It can cause the car to emit higher amounts of pollutants. These pollutants are responsible for the vehicle’s smog test failure.

2.  Dirty Air Filter

Dirty air filters can also lead to a car failing the smog test. They restrict the airflow to the engine. The consumption chamber is not receiving enough air. This leads to the engine running richer and, hence, producing more emissions, eventually causing the vehicle to fail the smog test.

3. Faulty Catalytic Converter

A catalytic converter is the most essential component in the exhaust, and it is simply impossible to pass a smog test with a faulty catalytic converter. It is the part that deals with harmful gases, including carbon monoxide and hydrocarbons, reducing pollutants. So, a faulty catalytic converter means that the exhaust still produces a high concentration of toxic gases, making it impossible for the vehicle to pass the test.

4. Bad Oxygen Sensor

An oxygen sensor is a device in a vehicle’s exhaust. It has a massive role in regulating and restricting the release of toxic gases from the car. Its purpose is to sense the amount of oxygen present in the exhaust. When not working correctly, the engine control module may put too much fuel in the combustion chamber. This causes the engine to run rich, hence increasing emissions and affecting the smog test.

5. Bad Spark Plugs

Spark plugs have a direct connection to the smog test. They have a fundamental function as they produce the spark that ignites the fuel and starts the engine. When the spark plug goes bad, it can make the engine misfire. This misfiring can alter the composition of emissions, affecting the smog test.

6. Faulty EVAP

EVAP stands for the evaporative emission control system, and it keeps gasoline vapors in the tank. It is designed to capture and recycle the fuel vapors before entering the environment. However, a leak in the EVAP system can allow the vapors to escape, increasing emissions and affecting the smog test readings.

These were the potential reasons your car might fail the smog test. It is essential to check these things and to have them fixed before taking a smog test.

How to Avoid Smog Test Failures?

Now, we will discuss the steps you must take for your vehicle to pass the test. This essentially involves avoiding the mistakes that lead to failure in the test. Below are the steps you need to take to pass the test.

1.    Regular Oil Changes: Timely oil change service is incredibly important for the overall functioning of the vehicle and is equally important to pass the smog test. You should change the oil every 5,000 to 7,500 to avoid it from becoming contaminated and increasing emissions.

2.    Changing Air Filter: Air filters also need to be regularly changed; you should replace the filters every 90 days so they do not be blocked and cause a restriction of airflow to the engine.

3.    Spark Plug Replacement: It is indispensable to change spark plugs on time as they are essential for the essential function of the vehicle. You should replace the spark plug every 30,000 miles to reduce emissions and pass the smog test.

4.    Maintaining Tire Pressure: The smog test also involves the vehicle being tested on a dynamometer, and that’s where tire pressure is critical. The technician drives the car on a dynamometer to obtain certain values. If the tires are not properly inflated, the vehicle will not be stable. This could alter the values and affect the test. So, it is important to get the tires adequately inflated before the smog test.

5.    Check Engine Light: The engine light is an excellent indication of the condition of the car’s engine or emission system. This means that there likely would be an increase in emissions. This could become a reason for the failed smog test. So keep an eye on the engine light, and take the car to a technician if it is on.

These tips can prove helpful before taking your car for a smog test. As you might have noticed, most are related to vehicle maintenance. So be sure to take your car to a technician regularly, especially before conducting a smog test.

About D&S Auto – Top Star Smog Check Center in Jurupa Valley!

A vehicle needs personalized vehicle-specific tuning to ace a smog test, and that is precisely what we provide at D&S Automotive. We proudly are the only certified smog testing and auto repair store in Jurupa Valley. Our team is ASE certified and boasts vast experience and knowledge of the industry. As a STAR Smog test repair center, we have undergone rigorous training to ensure your vehicle meets emission standards and avoids smog test failures. So visit us before your vehicle’s smog test and enjoy the best customer experience.