In some states, smog check stations will do a pre-test. This can also help the vehicle pass the smog test. Fuel additives are usually poured directly into the gas tank when filling up the car.Īdditives clean out the carbon deposits that build up in the intake and exhaust system. Step 7: Consider using a fuel additive, which can help lower emission levels. If the cap is damaged, replace it before the test.
The gas cap seals the fuel system, and if it is cracked or not fitted properly, it will trigger the Check Engine Light.This will cause your vehicle to fail the smog test. Under-inflated tires will make the engine work harder and could affect your results. Most states will run a dynamometer test on the vehicle, which puts the vehicle tires on rollers so the engine can run at high speeds without moving. Step 5: Check the tires to make sure they are properly inflated. The vehicle then needs to be driven for a couple of weeks so there is enough diagnostic data for the smog test. Note: In many cases, a mechanic will disconnect the battery while performing a tune-up, which will reset the vehicle’s computer.Have all filters changed and ask the mechanic to inspect all hoses to make sure there are no cracks or breaks. Step 4: Have the vehicle tuned up about two weeks before the test. While this will not guarantee a passing result, dirty oil can release additional pollutants. Step 3: Have the oil changed before the smog test. This will help the vehicle pass the smog test. The catalytic converter converts harmful emissions before they exit out the tailpipe.Ĭity driving doesn’t let the converter get hot enough to completely do its job, so taking it out on the highway will burn off the gas and oil residue in the converter. The car should be driven at highway speed for roughly two weeks before taking it in for a smog test.ĭriving at higher speeds will heat up the catalytic converter enough to burn out oil and gas residues. The takeaway here is to repair any issues related to the Check Engine Light before heading to the smog test. Ignoring an oxygen sensor failure can lead to catalytic converter damage which is a very expensive repair. Replacing an oxygen sensor is a relatively affordable repair. A failing oxygen sensor will cause a smog check failure. The oxygen sensor monitors the gas/air mixture being sent into the fuel injectors so the mixture can be adjusted if it is running rich or lean.
One of the most common reasons that the Check Engine Light will come on is a failing oxygen sensor. In almost all circumstances, the vehicle will fail if the Check Engine Light is illuminated. If this particular warning light is on you will need to the get the vehicle inspected and repaired before taking it in for a smog test. The Check Engine Light is almost entirely related to your emissions system. Step 1: Clear the Check Engine Light if it is on. Part 1 of 1: Getting your vehicle ready for an emissions test
Following are a few tips for making sure your vehicle gets a clean bill of health at the next smog test. If you are concerned that your vehicle may not pass its next smog test, there are steps you can take to increase the odds of a passing grade. Smog checks verify that a vehicle’s emissions system is working properly and the vehicle is not pushing pollutants into the air. Smog or emissions testing was introduced in the 1970s when the Clean Air Act went into effect. You can verify your state requirements at the local DMV. Still other states may require the car to be a certain age before a test is needed. Requirements vary by state: in some states you have to pass a test on a yearly basis, others may require a test every two years.
Smog tests are required by most states before a registration renewal. Nobody wants to fail an emissions or smog test: it means you have to figure out what caused the failure and get it fixed.