The goal of the 1970 Clean Air Act was to cut back on emissions from cars and factories. This created an entirely new industry: the smog check program. New York started the ball rolling in 1982 followed by California in 1984. Today, most states have emissions testing as part of the license renewal for their vehicles. Each state determines their own regulations for a smog test. Some require a test every two years. Others exempt certain cars depending upon how old they are. Not passing a smog test means you won’t be able to register your car and that can run into some serious complications. If you want to ace your smog test, then put this plan into action:

Fix Your Car First

You want to make sure your car is in good working condition before you show up for the smog test. Although it might not seem like it, the check engine light is a good indication that certain sensors need to be replaced and many of those sensors are tied directly to your emissions testing. The most common culprit is the oxygen sensor. A quick diagnosis at your mechanic will tell you exactly what is going on with those warning lights.

Drive at Highway Speeds for Two Weeks

If you use your car primarily for short trips, then you’ll want to hit the road and drive on the highway for at least two weeks prior to the test. This will go a long way towards clearing out your catalytic converter. Those short trips aren’t hot enough to burn out the residual gas and oil that may have accumulated in the exhaust. A decent long drive can help with that.

If you do drive on the highway but had your car repaired recently, then you want to clock in at least 200 miles before taking the test. That is because your battery might have been disconnected and the internal computer on the car rebooted.

Opt for A Pre-Inspection Test

At the same facility that runs your small test, you can get a pre-test. This can tell you what might be going on with your car that needs to be fixed. The difference between a pre-inspection test and the real test is that the pre-inspection results won’t be submitted to the government. If you fail the test and the results are submitted to the government, then the clock starts running as to when you will need to get the car fixed.

Get A Full Tank of Gas

At some inspection stations, a car could be put on an inclined which might expose the fuel pump. That in turn can allow more vapors to escape from the fuel line. If your tank is full, then those vapors will be minimized. Fill up before you go to the test. There are also certain fuel additives that can clear out carbon deposits. Ask your mechanic to make a recommendation for these additives and they might just help you score an “A” on your small test.