Five Star Smog is California's vehicle emissions testing program, run by the state's Bureau of Automotive Repair

Five Star Smog is not a single testing facility — it is California's official network of certified smog check stations. The state created the program to standardize how vehicles are tested for emissions compliance. Any station that meets Bureau of Automotive Repair standards can become a Five Star location, which means you will find these stations throughout California, not in one place.

When you need a smog check, a Five Star station performs the actual test. The station sends results directly to the California Department of Motor Vehicles through a system called STAR (Smog Test And Repair). Your vehicle either passes, fails, or receives a conditional pass. The station gives you a printed report and files the results with the state.

The Five Star name signals that the station meets state quality standards. This matters because not all smog check stations are equal — some are certified for basic testing only, while Five Star stations can perform both the initial test and, if needed, repairs. This matters to you because if your vehicle fails, a Five Star station can often fix the problem and retest without sending you elsewhere.

Key Takeaways

  • Five Star Smog stations are certified by California's Bureau of Automotive Repair and can perform both emissions testing and repairs at the same location.
  • The test checks your vehicle's emissions system, on-board diagnostic system, and tailpipe output — the specific test depends on your vehicle's age and type.
  • Results go directly to the California DMV through the STAR system, and you receive a printed report showing whether your vehicle passed, failed, or received a conditional pass.
  • If your vehicle fails, you have 30 days to repair it and return to any certified station for a retest, though returning to the same Five Star location often costs less.

What the smog check actually tests

The Five Star Smog test is not one test — it is a series of checks that vary based on your vehicle's year, make, and fuel type. For vehicles from 1996 forward, the test includes an on-board diagnostic (OBD) scan, which reads your vehicle's computer for emissions-related trouble codes. The technician plugs a scanner into your vehicle's diagnostic port and checks whether the system is ready to be tested.

Older vehicles (typically 1975 to 1995, depending on the model) undergo a different test called a two-speed idle test or loaded mode test. The vehicle sits on a dynamometer (a machine that simulates driving), and the technician measures what comes out of the tailpipe at different engine speeds. Diesel vehicles have their own protocol, which measures particulate matter and opacity rather than the same emissions a gasoline vehicle produces.

The test does not check your brakes, tires, or general mechanical condition. It focuses only on emissions — carbon monoxide, nitrogen oxides, hydrocarbons, and particulate matter. If your check engine light is on, the vehicle will likely fail the OBD portion because the computer has detected a problem the system cannot clear on its own.

How the testing process works from start to finish

When you arrive at a Five Star Smog station, bring your vehicle registration and proof of insurance. The technician will ask for your vehicle identification number (VIN) and mileage. They will visually inspect your vehicle for obvious emissions equipment tampering — a removed catalytic converter, for example, will fail you when ready.

For newer vehicles, the technician connects the OBD scanner and checks whether the system is ready. If the vehicle's computer shows that emissions monitors have not completed their self-checks (often because you recently cleared the codes or replaced the battery), the vehicle receives a conditional pass. This means you can register it, but you must return within 30 days with a vehicle that has completed its drive cycle so the monitors can finish their checks.

If the vehicle passes or receives a conditional pass, the technician prints your report and files it with the DMV through the STAR system. The whole process usually takes 15 to 30 minutes. If the vehicle fails, you receive a detailed report showing which emissions standard it did not meet. You then have 30 days to repair the vehicle and return for a retest at any certified station.

What happens if your vehicle fails

A failed smog check means your vehicle's emissions exceed California's limits. The report will specify what failed — the OBD system, tailpipe emissions, or both. Common failure reasons include a faulty oxygen sensor, a malfunctioning catalytic converter, a vacuum leak, or trouble codes the vehicle's computer cannot clear.

You have 30 days from the test date to repair the vehicle and retest. You can return to the same Five Star station or go to any other certified station. If you return to the same station, some offer discounted retests. If you go elsewhere, you will pay the full retest fee again, which typically ranges from $30 to $50 depending on the station and vehicle type.

If you repair the vehicle yourself or at an independent shop, bring it back to any certified station for the retest. If you have the repair done at the Five Star station where you failed, they will retest you as part of the repair service. Either way, the retest results go to the DMV the same way the original test did. You cannot register your vehicle until it passes.

Five Star stations versus other certified smog check locations

California has three types of certified smog check stations: test-only stations, repair stations, and Five Star stations. A test-only station performs the emissions test but cannot do repairs — if your vehicle fails, you must take it elsewhere. A repair station can test and repair but may not meet all Five Star standards. A Five Star station meets the highest state standards for equipment, training, and record-keeping.

The practical difference for you is convenience and cost. At a Five Star station, if your vehicle fails, the technician can often diagnose and repair the problem without you leaving. At a test-only station, you get the test result and then must find a repair shop, which costs time and potentially money for a second diagnostic. Five Star stations also have more rigorous oversight, which means less risk of a technician falsifying results or performing unnecessary repairs.

You are not required to use a Five Star station — any certified station's results are valid with the DMV. But if your vehicle has failed before or you want the option to repair and retest in one place, a Five Star location saves steps.

How to find a Five Star Smog station near you

The California Bureau of Automotive Repair maintains a searchable database of all certified smog check stations on its website. You can search by city, ZIP code, or station name. The database shows whether each station is test-only, repair, or Five Star certified. It also displays the station's hours and contact information.

When you search, filter for Five Star stations if you want the option to repair and retest at the same location. Call ahead to confirm the station is open and ask about their current wait time, especially during peak registration periods (late month and early year). Some stations require appointments; others take walk-ins. Ask about their retest fee if your vehicle fails — some Five Star stations offer discounts for retests.

You can also ask your regular mechanic for a referral. Many independent shops work closely with nearby Five Star stations and can tell you which ones have good reputations for fair pricing and accurate testing.

Frequently Asked Questions

Can I retest at a different station if I fail?

Yes. You can take your vehicle to any certified smog check station for a retest within 30 days of the original failure. You will pay the retest fee at the new station. Some Five Star stations offer discounted retests if you return to them, so it may be cheaper to go back to where you failed if the repair was done there.

What if my vehicle gets a conditional pass?

A conditional pass means your vehicle passed the visible inspection and the technician could not find emissions trouble codes, but the vehicle's computer monitors have not finished their self-checks. You can register your vehicle, but you must return within 30 days with a vehicle that has completed its drive cycle. Drive the vehicle normally for several days to let the monitors complete their checks, then retest.

How long does a smog check take?

Most smog checks take 15 to 30 minutes from arrival to printed report. Older vehicles may take slightly longer because the dynamometer test is more involved. If the station is busy, you may wait before the technician can see you. Call ahead to ask about current wait times.

Do I need an appointment at a Five Star station?

It depends on the station. Some Five Star locations accept walk-ins; others require appointments, especially during busy periods. Call the station before you go, or check the Bureau of Automotive Repair database, which sometimes lists whether appointments are required.

What documents do I need to bring?

Bring your vehicle registration and proof of insurance. The technician will need your VIN and current mileage. If your vehicle failed a previous smog check, bring that failure report so the technician knows what was tested before.