If you're a California driver, you'll eventually need a smog check. Whether it's your first time or you just want a refresher, this guide covers everything you need to know about California's emissions testing requirements.
What is a Smog Check?
A smog check (also called an emissions test or smog test) is a state-mandated inspection that measures the pollutants your vehicle produces. California has some of the strictest air quality standards in the country, and smog checks help keep our air clean.
During the test, a technician connects your vehicle to testing equipment that measures exhaust emissions. They also perform a visual inspection of emission control components and check your vehicle's onboard diagnostic (OBD) system.
Do I Need a Smog Check?
Here's who needs a smog check in California:
- Biennial smog check: Required every 2 years when renewing registration for vehicles 8 years or older
- Change of ownership: Required when selling or transferring a vehicle (with some exceptions)
- Initial registration: Required when registering an out-of-state vehicle in California
🚗 Vehicles Exempt from Smog Checks
- Gasoline-powered vehicles from model year 1975 or older
- Diesel vehicles from model year 1997 or older
- Electric and hydrogen fuel cell vehicles
- Natural gas vehicles with GVWR over 14,000 lbs
- Motorcycles
- New vehicles for the first 8 model years
How Much Does a Smog Check Cost?
Smog check prices in California vary by location, station type, and vehicle. Here's what you can expect:
| Service Type | Typical Cost |
|---|---|
| Regular Smog Check | $50 - $70 |
| STAR Certified Smog Check | $55 - $90 |
| Test-Only Station | $50 - $75 |
| Diesel Smog Check | $60 - $100 |
Prices on Lokali are displayed upfront, so you can compare stations and find the best deal near you before booking.
What is STAR Certified Smog?
STAR certification is a special designation from the California Bureau of Automotive Repair (BAR). STAR certified stations meet higher performance standards and are authorized to test vehicles that fail or are flagged as "gross polluters."
⚠️ Important: Check Your DMV Notice
If your DMV registration renewal notice says "STAR Station Required", you must go to a STAR certified station. Regular smog stations cannot test your vehicle. This is typically required for older vehicles or those with previous failed tests.
How to Know If You Need STAR
- Check your DMV renewal notice for "STAR Station Required"
- Vehicles directed to STAR stations are typically 15+ years old OR have failed previous tests
- Some randomly selected vehicles are also directed to STAR stations for quality assurance
What to Expect During Your Smog Check
A typical smog check takes 20-30 minutes. Here's what happens:
- Check-in: Provide your vehicle information and payment
- Visual inspection: Technician checks emission control components for tampering or damage
- OBD test: Computer connects to your vehicle's diagnostic port to read emission codes
- Functional test: Checks that your check engine light and other systems work correctly
- Results: You'll get a certificate of compliance (pass) or a printout showing why you failed
Tips for Passing Your Smog Check
- Drive your car for 20+ minutes before the test. This ensures your engine is warm and the catalytic converter is at operating temperature.
- Make sure your check engine light is off. If it's on, you'll automatically fail. Get it diagnosed and fixed first.
- Don't clear error codes right before the test. Your vehicle needs time to reset its monitors. If you recently cleared codes, drive 100+ miles before testing.
- Keep up with regular maintenance. Fresh spark plugs, clean air filter, and properly working oxygen sensors all help.
- Top off your gas tank. While not required, having at least 1/4 tank ensures accurate fuel system readings.
- Check your gas cap. A loose or damaged gas cap can cause emission codes and failures.
What If I Fail?
Don't panic! Here's what to do if your vehicle fails the smog check:
- Review the report: The technician will give you a printout showing exactly why you failed
- Get repairs: Fix the issues causing the failure (you may qualify for CAP assistance)
- Retest: Return to any smog station for a retest (some offer free retests if you did repairs there)
💰 Consumer Assistance Program (CAP)
California offers financial help for low-income vehicle owners who fail smog checks. You may qualify for up to $500 in repair assistance or up to $1,500 to retire your vehicle. Visit BAR's CAP page for details.
How to Book a Smog Check
Ready to get your smog check? Here's the easiest way:
- Go to Lokali.com
- Enter your zip code to find certified stations near you
- Compare prices, read reviews, and check availability
- Book online and get instant confirmation
- Show up at your appointment time—that's it!
Lokali shows you STAR certified stations, regular stations, and test-only stations so you can find exactly what you need.
Ready to Book Your Smog Check?
Find verified stations near you, compare prices, and book instantly online.
Book Smog Check Now →Frequently Asked Questions
How often do I need a smog check?
Every 2 years when renewing your vehicle registration, for vehicles 8 years or older.
Can I get a smog check if my check engine light is on?
You can get tested, but you'll automatically fail. Get the light diagnosed and repaired first.
How long is my smog certificate valid?
Smog certificates are valid for 90 days from the test date.
Do I need my title or registration for a smog check?
No, you just need to bring your vehicle and a form of payment. The station will look up your vehicle information.
Can I smog my car after hours?
Some stations offer extended hours. On Lokali, you can filter by availability and book appointments that fit your schedule.