Green Smog Check basics
Green Smog Check is California's vehicle emissions inspection program for cars, trucks, and motorcycles that run on alternative fuels — primarily electric vehicles (EVs), hydrogen fuel cell vehicles, and plug-in hybrids. Unlike the standard Smog Check for gasoline and diesel vehicles, Green Smog Check focuses on verifying that the vehicle's emissions control systems are functioning correctly for its fuel type.
If you own an alternative-fuel vehicle in California, you still need to pass an emissions test every two years (or annually for vehicles over 16 years old, depending on your county). Green Smog Check stations are authorized to test these vehicles and issue the certificate you need to register or renew your vehicle with the California Department of Motor Vehicles (DMV).
The test itself is typically faster and less invasive than a traditional Smog Check because alternative-fuel vehicles produce fewer or zero tailpipe emissions. A technician will inspect your vehicle's emissions equipment, run a diagnostic scan, and verify that all systems are in working order.
Key Takeaways
- Green Smog Check applies to electric vehicles, hydrogen fuel cell vehicles, and plug-in hybrids registered in California.
- You must pass Green Smog Check every two years (or annually for older vehicles) to renew your vehicle registration.
- The test checks that your vehicle's emissions control systems are functioning correctly for its fuel type, not just tailpipe emissions.
- You can find authorized Green Smog Check stations through the California Bureau of Automotive Repair website or by calling your local smog referee.
- If your vehicle fails, the technician will provide a report showing what needs to be repaired before you can pass.
Which vehicles need Green Smog Check
Green Smog Check is required for electric vehicles, hydrogen fuel cell vehicles, and plug-in hybrid electric vehicles (PHEVs) registered in California. If your vehicle runs entirely on electricity or hydrogen, or combines an electric motor with a gas engine, you fall under this program.
Standard gasoline and diesel vehicles use the traditional Smog Check program instead. If you are unsure which category your vehicle falls into, check your vehicle's registration documents or contact your local smog referee — they can tell you which test your vehicle needs based on its fuel type and model year.
Vehicles that are exempt from Smog Check altogether (such as brand-new vehicles under a certain model year, or vehicles that have not been registered in California for at least 18 months) may also be exempt from Green Smog Check. Your DMV notice will indicate whether your vehicle requires testing.
What the Green Smog Check test includes
A Green Smog Check technician will perform a visual inspection of your vehicle's emissions control equipment, including the battery management system, electric motor components, and any hybrid-specific systems. They will look for signs of damage, corrosion, or disconnected parts that could affect emissions performance.
The technician will also connect a diagnostic scanner to your vehicle's onboard computer to check for any fault codes related to emissions systems. For electric vehicles, this may include checking the battery status, charging system, and motor controller. For plug-in hybrids, the test covers both the electric and gas-powered components.
Unlike traditional Smog Check, Green Smog Check does not involve a tailpipe emissions test, since electric and hydrogen vehicles produce zero or near-zero emissions. The focus is on verifying that all systems designed to control emissions are present and functioning.
Finding an authorized Green Smog Check station
You can find authorized Green Smog Check stations through the California Bureau of Automotive Repair (BAR) website at bar.ca.gov. Use their station locator tool and filter for stations that perform Green Smog Check testing. You can search by zip code or city to find the nearest location.
Alternatively, contact your local smog referee's office — they maintain a list of authorized stations in your county and can tell you which ones test alternative-fuel vehicles. Your county's environmental health department can provide the smog referee's phone number, or you can search online for "[your county] smog referee."
When you call ahead, confirm that the station is authorized for your specific vehicle type. Some stations may test all alternative-fuel vehicles, while others specialize in certain types (such as EVs only). Having your vehicle's year, make, model, and fuel type ready will help the station confirm they can test it.
What happens if your vehicle fails
If your vehicle fails Green Smog Check, the technician will provide you with a detailed report showing which emissions systems did not pass and what repairs are needed. Common failure reasons include a faulty battery management system, a disconnected emissions component, or a fault code in the onboard computer.
You have 30 days from the test date to have the vehicle repaired and retested at no additional cost at the same station. Keep your failure report and bring it with you when you return. If you repair the vehicle at a different shop, bring the repair documentation to the retest appointment so the technician knows what was fixed.
Once your vehicle passes the retest, the station will issue your Smog Check certificate. You can then take this certificate to the DMV to complete your vehicle registration renewal. If you do not pass the retest within 30 days, you will need to pay for another full test.
Cost and timing for Green Smog Check
The cost of Green Smog Check varies by station but is typically between $30 and $50 for the initial test. Some stations may charge slightly more for retests or for testing certain vehicle types. Call ahead to confirm the exact price at your chosen station.
The test itself usually takes 15 to 30 minutes, depending on how quickly the diagnostic scan completes and whether any issues are found. You do not need an appointment at most stations, but calling ahead can save you a wait, especially during busy registration renewal periods.
Plan to have your test completed before your vehicle registration expires. Your DMV renewal notice will show your expiration date. If you test after your registration has expired, you may face late fees when you renew.
Preparing your vehicle for Green Smog Check
Before you take your vehicle in for testing, make sure the battery is fully charged (for electric vehicles) or charged to a normal operating level (for plug-in hybrids). A low battery can sometimes trigger fault codes that may cause a test failure.
Check that all visible emissions equipment is intact and properly connected. Look under the hood for any loose hoses, disconnected wires, or damaged components related to the emissions system. If you notice anything obviously wrong, have it repaired before the test.
Bring your vehicle registration documents and a valid photo ID to the testing station. Have your vehicle's VIN (vehicle identification number) ready — it appears on your registration and on the driver's side of the windshield. The technician will need this information to complete your test certificate.
Frequently Asked Questions
Do I need Green Smog Check if I own a brand-new electric vehicle?
Brand-new vehicles are typically exempt from Smog Check for the first few model years. Check your DMV renewal notice to see if testing is required. If your notice does not mention Smog Check, you do not need it yet. Once you receive a notice requiring testing, Green Smog Check will explore.
What if my plug-in hybrid fails because of the gas engine part?
Plug-in hybrids are tested on both their electric and gas-powered systems. If the gas engine component fails, you will need to have that part repaired by a mechanic. The failure report will specify which system failed so you know where to focus repairs.
Can I drive my vehicle if it fails Green Smog Check?
Yes, you can drive your vehicle while waiting for repairs. However, you cannot renew your vehicle registration until you pass the test. If your registration expires before you pass, you may face late fees and cannot legally drive the vehicle.
How often do I need to renew my Green Smog Check certificate?
Most vehicles need Green Smog Check every two years. Vehicles over 16 years old may need it annually, depending on your county. Your DMV renewal notice will specify the testing frequency for your vehicle.
What if the station says they cannot test my vehicle?
Some stations may not be equipped to test certain alternative-fuel vehicles. Contact your local smog referee or the California Bureau of Automotive Repair to find a station that specializes in your vehicle type. Do not assume the first station you call is your only option.