Short answer: usually yes, and it's the seller's responsibility. When you sell most gasoline cars in California, you have to give the buyer a valid smog certification, and selling the car "as is" doesn't change that.
This guide explains who needs one, how long it is valid, which vehicles are exempt, and what to do if your car fails. It is general information, not legal advice. The Bureau of Automotive Repair (BAR) and DMV set these rules and can change them, so check bar.ca.gov and dmv.ca.gov for your exact vehicle.
The basic rule
For a change of ownership, California requires a smog certification for most vehicles that are subject to the Smog Check program. The seller is responsible for providing it.
- The certificate must be issued within 90 days of the transfer.
- The smog station reports the result to DMV electronically. The buyer needs it on record to register the car.
- Writing "buyer responsible for smog" or "sold as is" on the paperwork does not move the legal responsibility off the seller.
Which vehicles need a smog certificate to sell
In general, a smog certification is needed to transfer:
- Gasoline vehicles that are model year 1976 or newer and more than four model years old.
- Hybrid vehicles in the same age range.
- Diesel vehicles from model year 1998 or newer with a gross vehicle weight rating (GVWR) of 14,000 lbs or less.
Common exemptions
You generally do not need a smog certificate to sell:
| Vehicle or situation | Notes |
|---|---|
| Gasoline vehicles four or fewer model years old | The buyer pays a smog transfer fee at DMV instead |
| Gasoline vehicles model year 1975 or older | Exempt from Smog Check |
| Diesel vehicles model year 1997 or older, or over 14,000 lbs GVWR | Exempt from Smog Check |
| Fully electric vehicles | No tailpipe test |
| Motorcycles and trailers | Not in the Smog Check program |
| Transfers between family members | Spouse, domestic partner, parent, child, grandparent, grandchild or sibling. DMV uses a Statement of Facts (REG 256) for this. Not if the relative bought the car for you without first titling it in their name |
Living in a rural area usually doesn't change this. Some rural ZIP codes don't need a smog check for registration renewal, but BAR still requires one there when the car changes ownership. If you aren't sure about your area, check your ZIP code on BAR's website.
The 90-day window
A smog certificate is valid for 90 days from the test. If your car passed a smog check for its registration renewal within the last 90 days, that result generally covers a sale too. If you aren't sure, ask the smog station or check DMV's record before you sell.
Practical tip: get the smog check done before you list the car. Then you can tell buyers "fresh smog" (a real selling point), and you won't discover a problem halfway through a sale.
Where to get it
Any licensed Smog Check station can test most vehicles. Some vehicles are directed to a STAR-certified station. Your DMV renewal notice says so if yours is one of them. Prices vary by station, so it's worth calling two or three.
Bring the car warmed up and with the check engine light off. A lit check engine light is an automatic fail.
If the car fails
You have a few options:
- Repair it and retest. Get a written diagnosis, then decide whether the repair makes sense for the car's value.
- Check BAR's Consumer Assistance Program (CAP). For eligible owners, CAP offers repair assistance after a failed smog check, or payment to retire the vehicle at a licensed dismantler. Repair assistance applies to a failed biennial (renewal) Smog Check, not a change-of-ownership test. Neither option is available while the car is in the middle of a transfer of ownership, so CAP won't help with a sale that is already under way. Eligibility rules and amounts change, so check bar.ca.gov. Retirement generally requires the car to be currently registered and able to move under its own power.
- Sell it with full disclosure. Some buyers, such as mechanics, dealers and dismantlers, buy cars that need work. Be honest that the car failed and why. Keep in mind that the law still puts the smog requirement on the seller in a normal private sale, and that the buyer can't register the car without it.
What about a car that doesn't run?
A non-running car still needs a smog certificate for a normal ownership transfer unless it is exempt, which is a problem if it can't be driven to a station. The usual options:
- Fix it enough to run and test it, if the numbers make sense.
- Sell it to a licensed dismantler for parts or scrap. Dismantling uses different DMV paperwork. Ask the dismantler what they need from you.
- Sell it to a buyer who plans to repair it, with clear written disclosure of its condition and smog status.
Our guide Selling a car that doesn't run in San Diego or LA covers all of these in more detail.
Smog and online auctions
On an auction, buyers bid based on what the listing says. If you have a recent smog certificate, say so and include the date. If you don't, or the car failed, say that too. An honest listing avoids disputes and fallen-through sales.
On the Auction Direct Marketplace (open in Los Angeles, Riverside, San Bernardino and San Diego counties), every listing includes a condition report, plus engine audio when the car runs, and buyers see exactly what you disclose. Running or not, title or not, we'll help you sell it. Local buyers, licensed dealers, and for non-runners dismantlers and junkyards bid live. Start your listing: it's free through December 31, 2026 (normally $25, no commission).
Checklist for sellers
- Check whether your car is exempt: age, fuel type, electric, or a family transfer.
- If it isn't exempt, get a smog check within 90 days before the sale.
- Mention the smog status clearly in your listing.
- Give the buyer the certificate information along with the signed title and the bill of sale (REG 135).
- File your release of liability (REG 138) within 5 days. See our REG 138 guide.
For the whole process from start to finish, read how to sell a car in California.