California Engine Swap Smog Laws

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California has its fair share of car enthusiasts. For anyone who fits that description, it's important to know that the state has strict laws governing engine replacement. To ensure compliance, the California Bureau of Automotive Repair requires that when someone changes the engine on a vehicle, it must pass certification and inspection before being allowed to legally operate on California roads. After that, it is subject to the same smog rules as every other vehicle in the state.

The California engine change laws are intended to make sure that, after an engine swap, the new engine/transmission does not put more pollutants into the air than the original engine/transmission. To that end, the new engine must be no older than the vehicle and have fully functional emissions controls.

California Engine Swap Laws

The Bureau of Automotive Repair (BAR) may sound like someplace to take a car that needs mechanical work. However, it is a regulatory agency, part of the California Department of Consumer Affairs. It is charged with enforcing the stringent California engine change laws that prohibit any mixing and matching of components as part of an engine change, not even variants of the same engine in a manufacturer's line.

Together with the California Air Resources Board, the California BAR developed guidelines for swapping out engines. The intention is to provide a structure for engine changes in California while maintaining excellent air quality. Both California and federal laws forbid any changes or modifications to a vehicle's original emission control system configuration as certified by the manufacturer.

For example, California Vehicle Code Section 27156 prohibits anyone from disconnecting or altering any required motor vehicle pollution control device. Similarly, California Code of Regulations Section 3362.1 makes it illegal for an auto repair dealer to change an engine in any way that reduces the effectiveness of the original emission control system or any of its components. Given the difficulties the laws impose, the BAR recommends that a car owner consider rebuilding the original engine instead of swapping it out.

Vehicle Certification and Emissions Test After Engine Swap

Once a vehicle owner has done a legal engine change, installing an engine with all required smog equipment and controls for both the engine and transmission, they are not finished. It is necessary to make an inspection appointment at a BAR referee station.

The inspector will conduct a visual inspection to see if all of the required parts are present and all engine swap laws have been followed. If so, they place a BAR inspection label in the door jamb or engine compartment of the vehicle. Then they check the vehicle's tailpipe emissions and perform a functional inspection.

Those that pass will be provided the smog check inspection certificate that allows the owner to register the vehicle. Note that the vehicle with the swapped engine will, in the future, be required to comply with all California smog inspection rules, just like other vehicles.

California Biennial Smog Check Requirements

Californians own a lot of cars, SUVs and trucks. In fact, the state has the highest number of registered vehicles in the country, currently over 14 million. It is eighth in the nation in registered vehicles per capita. All these vehicles means lots of smog concerns.

Today, California takes its air quality very seriously and mandates emissions inspections – better known as smog tests – for all vehicles registered in the state of California. Vehicles registered in populated counties or populated rural Zip codes are subject to the biennial smog certification program. This means that the owner must take the vehicle in for smog testing as part of every second registration renewal. Counties like San Francisco, Los Angeles, Sacramento, Santa Cruz, Santa Barbara, Orange, Alameda, San Luis Obispo, Marin, Contra Costa, Fresno, Napa and Monterey Counties fall into the every-other-year category.

Exemptions from California Smog Check Program

Some new and some older vehicles in these urban counties are exempted. For example, gasoline-powered vehicles that are within the newest eight vehicle registration model years are exempted from biennial smog testing but must pay a smog abatement fee every one of those years. Any gasoline-powered vehicle that was made in a model year of 1975 or earlier, including motorcycles, are exempted.

Some diesel-powered vehicles are also excluded. Those of model years 1997 or earlier do not have to do the every-two-year testing. Nor do those vehicles with a gross vehicle weight rating (GVWR) of under 14,000 pounds.

New Smog Rules for 2021

Are there new California laws and regulations in 2021 regarding vehicle emissions? There are. New smog laws in California in 2021 are basically concerned with several categories of regulations, Vehicle Safety Recall Information, testing of a vehicle’s ECM, and an increased amount of vehicle retirement options.

As of July 19, 2021, the California Air Resource Board (CARB), changed the scope of a smog test. The every-two-registrations test will now include testing to determine whether a vehicle’s Engine Control Module has been changed beyond OEM settings, through tuning and manipulation that has not been approved by CARB. The OEM is itself an emissions control device, and it has long been the law that legal modifications to it can only be done with a CARB Executive Order number. Under the new law, all vehicles containing software that has not been approved will fail the smog test.

Vehicle Information Database

Another change to the smog check procedure in California occurred in 2021. This gives the owner specific recall information applicable to their vehicle from a Vehicle Information Database. This recall information can include the date of recall, the number of the recall campaign and an explanation of the recall. The owner gets a copy of the Vehicle Inspection Report that contains all this recall information.

Vehicle Retirement Incentives

The third area of change in 2021 involves vehicles that do not pass smog testing. It increases the vehicle retirement option to $1,500 for low-income owners and $1,000 for all others. The regulations also increase repair assistance contributions to between $900 and $1200 depending on the vehicle's model year. This law is intended to make it more attractive to retire an old vehicle than it is to sell it to cash-for-cars companies.