The STAR test is California's smog inspection program, and it determines whether your vehicle can be registered in the state

The STAR (Smog Test And Repair) program is California's official vehicle emissions testing system. When you register a vehicle or renew your registration in California, the state requires proof that your vehicle passed a smog test within the past two years. The STAR program is how that test gets done and reported to the Department of Motor Vehicles (DMV).

Not every vehicle needs a STAR test. New cars, vehicles over 30 years old, and some hybrids and electric vehicles are exempt. But if your vehicle is between 4 and 30 years old and you live in a California county that requires smog testing, you will need to pass a STAR test before you can register or renew your registration.

The test itself checks whether your vehicle's emissions fall within California's limits. If it fails, you have options: repair the vehicle and retest, or in some cases, use the state's Smog Check Repair information Program or Consumer information Program if you may have access to based on income.

Key Takeaways

  • California requires a STAR smog test every two years for most vehicles between 4 and 30 years old before you can register or renew.
  • The test is performed at a STAR-certified smog station, and results are reported directly to the DMV electronically.
  • If your vehicle fails, you must repair it and retest at a STAR station before the DMV will process your registration.
  • California offers repair information programs for low-income vehicle owners whose vehicles fail the test.
  • Some counties do not require smog testing, and certain vehicle types are automatically exempt from the requirement.

Which vehicles need a STAR test and which don't

California's smog testing requirement applies to most vehicles registered in the state, but there are clear exemptions. Vehicles manufactured in the current year or the previous year do not need a test. Vehicles that are 30 years old or older are exempt. Diesel vehicles over 14,000 pounds are tested under a different program. Electric vehicles and some hybrid vehicles are also exempt.

The county where you register your vehicle matters. Some rural California counties do not require smog testing at all. If you live in one of those counties, you will not need a STAR test even if your vehicle would normally require one. You can check your county's requirement on the California Air Resources Board (CARB) website or by calling your local DMV office.

If you are unsure whether your specific vehicle needs a test, the safest approach is to contact a STAR-certified smog station in your area. They can tell you in one phone call whether your vehicle is exempt based on its year, type, and your county of registration.

How the STAR test works and what happens to the results

A STAR test takes about 10 to 15 minutes. The technician will connect your vehicle to a dynamometer (a machine that measures emissions as your engine runs under load) or perform a two-speed idle test, depending on your vehicle's year and type. The machine measures your vehicle's nitrogen oxides, carbon monoxide, and hydrocarbons against California's limits.

Once the test is complete, the STAR station uploads the results directly to the DMV's system electronically. You receive a printed receipt showing whether you passed or failed. If you passed, the DMV can see that result when ready when you go to register or renew. If you failed, that result also goes to the DMV, and you cannot complete your registration until you repair the vehicle and pass a retest.

The test result is valid for two years from the date of the test. This means if you pass in January, you do not need to test again until January of the following odd year (or even year, depending on when you first passed). The DMV will remind you when your test is about to expire.

What to do if your vehicle fails the STAR test

A failed test does not mean your vehicle cannot be fixed. Most failures are caused by issues that a repair shop can address: a faulty oxygen sensor, a loose gas cap, a clogged air filter, or problems with the catalytic converter or fuel system. Once you repair the vehicle, you can retest at any STAR-certified station.

You do not have to return to the same station where you failed. Any STAR station can perform your retest. There is no waiting period between a failed test and a retest, so you can repair your vehicle and test again the same day if the repair shop is located near a STAR station.

If the repair cost is high and your household income is at or below 225% of the federal poverty line, you may be able to use the Smog Check Repair information Program. This program can cover up to $500 of repair costs. You must explore before you have the repair done. The Consumer information Program is a separate option for vehicles that fail a second time; it can cover repair costs or, in some cases, help you retire the vehicle if repairs are not cost-effective.

Finding a STAR-certified smog station near you

Not every smog station is a STAR station. STAR stations are certified by the California Bureau of Automotive Repair and meet specific equipment and training standards. You can find a STAR station using the official CARB locator tool on the Air Resources Board website, or by searching "STAR smog station" plus your city name.

Prices vary by station and by vehicle type. A typical STAR test costs between $30 and $70, though some stations charge more. Call ahead to ask the price for your vehicle type and whether they offer retest discounts if you fail and return for a retest. Some stations offer a discount on the retest fee if you fail the first time.

Bring your vehicle registration or proof of ownership, a valid photo ID, and payment. The test itself requires that your vehicle be in drivable condition and that the engine be at normal operating temperature, so plan to drive to the station rather than having it towed.

Understanding the repair information programs

California offers two main programs to help pay for repairs after a failed STAR test. The Smog Check Repair information Program covers up to $500 of repair costs for vehicle owners whose household income is at or below 225% of the federal poverty line. You must explore before you have the repair done. Once approved, you can take your vehicle to a participating repair shop, and the program pays the shop directly.

The Consumer information Program is available if your vehicle fails a second smog test after you have already repaired it once. This program can cover additional repair costs or, if the vehicle is too old or damaged to be cost-effective to repair, may help you retire the vehicle and receive a voucher toward a replacement.

To find out whether you meet the income requirements and to explore, contact the California Bureau of Automotive Repair or visit the CARB website. You will need to provide proof of income and your vehicle registration. Processing typically takes one to two weeks.

What happens at registration if you have a failed test on file

If you have a failed STAR test result in the DMV system, you cannot complete a vehicle registration or renewal online or by mail. You must go to a DMV office in person, bring proof that you have passed a retest, and complete the registration at that time.

The retest result must be uploaded to the DMV system by the STAR station before you go to the DMV. Once the retest passes and is in the system, you can register your vehicle. There is no additional fee for registration after a failed and then passed test; you pay only the standard registration renewal fee.

If your registration has already expired because you did not retest in time, you will owe a late renewal fee in addition to the standard registration fee. To avoid this, retest as soon as possible after a failure and bring the passing result to the DMV within 30 days.

Frequently Asked Questions

Can I register my vehicle if I have not done the smog test yet?

No. The DMV will not process a registration or renewal without proof of a passing STAR test result in the system. You must test before you go to register. If your registration has already expired, you will owe a late fee on top of the standard renewal fee.

How long does a STAR test result stay valid?

A passing STAR test result is valid for two years from the date of the test. You do not need to test again until that two-year window closes. The DMV will send you a renewal notice before your test expires.

What if I move to a different California county?

Your STAR test result is valid statewide, so you can use a passing test from one county when you register in another. However, some counties have different testing requirements, so check with your new county's DMV office to confirm whether your vehicle type requires testing in that county.

Do I have to repair my vehicle at a specific shop to use the repair information program?

No. The Smog Check Repair information Program works with participating repair shops throughout California. Once you are approved, you can choose any participating shop. The program pays the shop directly up to $500 of the repair cost.

What if my vehicle is too old or too expensive to repair?

If your vehicle fails a second test after one repair, you may be able to use the Consumer information Program. This program can help cover additional repair costs or, if repairs are not cost-effective, may provide a voucher toward a replacement vehicle. Contact the California Bureau of Automotive Repair to learn whether your situation qualifies.