Tahoe car care: The California smog check

Sheila Greeno
Special to the Sun

TRUCKEE, Calif. – In 1956 a “killer smog” covered London and was attributed to more than 4,000 deaths. While many either don’t remember this event or were yet to be born, it was one of the first significant event that spurred the idea of protecting the Earth’s air quality. At this time California was already taking the smog problem seriously.

Today, six decades later, California has passed thousands of legislative actions and regulations to help curb the production of air pollution in our state.

Like it or not, one of the responsibilities of owning a vehicle includes keeping it emissions clean and not becoming a contributor to poor air quality. With 32 million registered vehicles on the road in California, it is no wonder that our state has the strictest vehicle emissions standards in the country.

The DMV reminds drivers on the annual registration renewal notice if a smog check is needed. For most vehicles six years or older, this is a mandatory test every two years. Diesel vehicles are now tested every year. Additionally, a vehicle brought in from out of sate is required to pass a smog test in order to be registered in California.

Bill Greeno, owner of Quality Automotive and Smog, states that about 90 percent of vehicles tested at the shop pass the test the first time. He suggests that vehicle owners familiarize themselves with some of the procedures ahead of time to avoid potential problems that could keep the vehicle from passing.

When you visit a California Smog Check Station, it is important to know that you are having a test performed on your vehicle as opposed to a service. The technician is certified and regulated by the California Bureau of Automotive Repair to test vehicles on calibrated equipment that instantly downloads all the data to the State of California. The technician will administer three tests, an emission inspection, visual inspection, and a functional test. The vehicle must pass all three tests to be smog certified.

The emissions test measures the vehicle’s Hydrocarbons (HC), Carbon Monoxides (CO) and Nitrides of Oxygen Oxides, the three undesired chemicals responsible for smog. Emissions must fall within the allowable limits set by the California Air Resources Board. A properly maintained engine should not have any trouble passing the emissions test.

During the visual inspection, the smog technician verifies that all emissions components on the vehicle are present and properly connected. The smog technician is also looking for any defective or disconnected electrical connections, vacuum hoses and/or any modification which would effect engine performance and ultimately increase harmful smog emissions. There is also an inspection for visible black or white smoke from the tailpipe.

The last test is the functional inspection which examines the On Board Diagnostic (OBD) system. This test includes inspection for any fault codes in the vehicle’s computer. The test also requires that engine timing and idle speed fall within the manufacturer’s guidelines. During this inspection if the check engine light is on or comes on, even briefly, the vehicle will fail.

Also, it is important to know that if the check engine light has recently been turned off or if the battery has been disconnected, it will be necessary to drive the vehicle a few days before attempting a smog test. Failing a smog test and what to do about it is the subject of my next article, so keep an eye on this page.

When you visit your local smog testing facility, bring your registration renewal notice with you. The technician will scan your information and test results will be sent to the DMV. Once registration fees are paid, a new sticker will be mailed to the vehicle owner.

– This article was submitted to the Sun from Quality Automotive and Smog, located at 11357 Deerfield Drive in Truckee. Learn more about the business at

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