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Selling a Used Car in California – Smog Tests

If you’re shopping for a used car in California, something you might be wondering about — and if you’re not wondering about it, you should for the reasons I’ll describe — is whether or not a smog check needs to be done. If you’re looking on a website like Craigslist where anyone can post a vehicle for sale, for example, you might see a lot of ads where the seller says:

  • The smog test is the buyer’s responsibility,
  • The vehicle passed smog “6 months ago”, or
  • The vehicle is “smog ready”

I’ve always assumed that “smog ready” means the vehicle can pass a smog test which, if you think about it, could have two possible meanings: (1) the vehicle will pass smog and the seller agrees to do that as a condition of the sale, or (2) the vehicle will allegedly pass smog, but the buyer has to buy the car first and bear the risk of it not actually passing smog.

So the question for this blog post is this: what is the rule about smog tests when you’re buying a new car in California?

Two things before we dive in to the answer:

  • First, if you’re not in California and don’t know what a smog test is, it’s an emissions test that your car has to pass in order to get registered in California. Smog tests are, thus, an air pollution control measure. If your car can’t pass a smog test and you can’t fix it, then you cannot register it in California. Depending on your situation, you may be able to sell your car to your local air quality management district. The rules for what vehicles have to be smogged are very involved so there’s no way for me to go over all of them in this post. To whet your appetite, though, two very common rules are: (1) motorcycles are exempt from smog testing, and (b) vehicles from before 1975 are also exempt from smog testing. If you buy a new vehicle in California, it is generally exempt from a smog test for the first six years of ownership, although it may be four years in some cases. Again, there are many different possible permutations for when a smog test is and is not required so you’ll need to check what particular rules apply to your situation.
  • Second, buying and selling vehicles falls in to many different categories that, again, I cannot possibly go over in this post. Some examples are: (1) vehicles that are sold for scrap or dismantling, (2) car dealers selling to one another, (3) vehicles being sold between family members, (4) vehicles that were leased, and (5) vehicles meant for off-road use. Special rules may apply in those situations as to whether a smog test is required when those vehicles are sold as used.

In my opinion — which, as always, is not comprehensive or necessarily representative of your life — the most common “used car purchasing” situation is where a private individual buys a used car (e.g. off their local Craigslist) from another private individual for the buyer’s own personal use. This post will answer the question: is the seller in such a situation required to do a smog check prior to finalizing the sale? Phrased alternatively, is the buyer in such a situation entitled to a passing smog test as part of the sale?

The Answer:
To both questions: Yes, assuming that a passing smog test was not performed in the 90 calendar days before the sale.

The Explanation:
I read statutes all the time and even I admit that California could make the law here less confusing. To understand where the general rule of “seller of a used car must provide a passing smog test result as part of the sale” comes from, a good place to start would be California Vehicle Code section 24007(b)(1) and (b)(2) which state:

(b)(1) Except as provided in Section 24007.5, no person shall sell, or offer or deliver for sale, to the ultimate purchaser, or to any subsequent purchaser a new or used motor vehicle, as those terms are defined in Chapter 2 (commencing with Section 39010) of Part 1 of Division 26 of the Health and Safety Code, subject to Part 5 (commencing with Section 43000) of that Division 26 which is not in compliance with that part and the rules and regulations of the State Air Resources Board, unless the vehicle is sold to a dealer or sold for the purpose of being legally wrecked or dismantled.

(2) Prior to or at the time of delivery for sale, the seller shall provide the purchaser a valid certificate of compliance or certificate of noncompliance, as appropriate, issued in accordance with Section 44015 of the Health and Safety Code.

The part I’ve bolded and underlined above about certificates of compliance and noncompliance basically refer to smog tests. If you want to delve in to that, you can look up California Health and Safety Code section 44015. If you do, the rule that smog tests on used cars are only good for 90 days is in section 44015(e). You can also take a look at California Vehicle Code section 4000.1(d)(1) to see that a passing smog certificate is only good for 90 days.

If you’re looking for the law that says you have to have a passing smog test in order to register your car in California, that’s also in Vehicle Code section 4000.1, although this time it’s subsection (a).

What Does All of This Mean?
The confusing aspect I described earlier is that you have to read all three of these statutes together. If you do, you get:

  • Vehicle Code 24007(b) for the requirement that, in most cases, the seller has to provide a passing smog test with the sale,
  • Health and Safety Code section 44015 for the requirement of how the smog test has to be done and that it has to be from within the 90 days preceding the sale, and
  • Vehicle Code section 4000.1(a) for the requirement that a passing smog test within the last 90 days is required in order to register the vehicle in California.

As you can probably guess, the idea behind requiring the seller to produce a valid smog test is so that the buyer isn’t stuck in the situation of having paid a bunch of money for a car that they can’t register.

If you’re in a situation where you bought a car in California and can’t register it, there are a few things you could do:

  • Obviously, if you bought the car and knowingly waived the right to receive a smog test from the seller, then I would say it’s your own fault that you can’t register the car now. You took the gamble and you lost.
  • If you had no idea it was your right to get the seller to provide a smog test, you have at least two paths I can think of: (1) sue the seller and demand he or she refund your money and take the car back, or (2) deem it a lesson learned and just let it go. (2) is probably not real palatable for most people. (1), however, may not be realistic for most people either.

The best way, I think, to avoid this dilemma is to nip it in the proverbial bud before it ever arises: if you’re buying a used car from an individual, check to see if the seller is required to provide you a valid smog test and, if so, then insist on getting it. If you buy the car without the smog test, then you run the risk of not being able to register the car in California.


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Andy Chen

Andy I. Chen is a lawyer licensed to practice law in California and New York. Andy maintains offices in Los Altos, California and Modesto, California. Under the New York Court of Appeals' 2015 decision in Schoenefeld v. State of New York, Andy does not accept cases from those in New York state. He does, however, know many lawyers in New York state and would be happy to make a referral.


  1. Really no mattеr if someone doeѕn’t know afteгward its up
    to other viewers thаt they will help, so here it happens.

  2. If it’s the Law or is posted on the DMV website that the seller is responsible to make repairs necessary for the smog test even after the sale (which is what the DMV states http://www.dmv.org/ca-california/buy-sell/state-regulations.php), then why is small claims court not listed as an option to get repaid for the repairs needed for Title?

      • I bought a 1999 F350 7.3 diesel. With pink slip .was told it had a clean title . No issue , And registration was good for 30 more days. It runs great. When I registered it at AAA DMV . Learned it had a salvage title. Went to smog shop. Failed. The check engine light was taking out and it has a code a the rong emission sticker on the truck .
        Then went

  3. So if I’m buying a 2014 model year car in January 2018 do I need a smog test from the seller at time of purchase?

    • Yeah, because like the document states, if you buy the vehicle without the seller doing the smog check and providing with the paper work including the title, its ineligible to be registered regardless. So if the seller didn’t know that, and or expected you to pay for it, he was ill informed and needs to take care of that smog check before the sale. I’m in that current situation as well.

      • What happens if you purchase a car from a dealership they provided a smog certificate at time of sale but two years later dmv requires smog for the vehicle and you have been refereed to a ca gov smog station due to the previous smog station being audited and your car was deemed a illegal smog. Which means my smog certificate was illegal at point of sale. Who’s responsible ?

    • I bought a car from someone that says he has a dealers liscense but didnt sell mine under it. But after purchasing he registered it near buy left to get a smog and gave me title current registration then had me sign an as is. Shortly after driving away check engine light came on but didnt want to panic. Had my mechanic do diagnostic and codes came up, i bought parts and repaired. After oil changed he noticed oil milky. Right after engine blew. Seller blaimed me and its its been a battle and said he’ll give me another but it was one that was cheaper and said i hVe to go half on repairing the one that broke. I spoke with the automotive repair bureau and pulled up smog and said their were stored codes which means tbe seller was aware but posted it as good car, no leaks or lights on. Hes refusing to give back my money. Is it unlawful to sell a car that wasnt in smog compliance? What should i do?

      • I am in almost the exact same situation except our mechanic caught the issue as soon as the check engine light came on 6 days after purchase and it is now not drivable until very expensive repairs are made. Did you find a way to resolve this? Any tips?

      • I had just bought a car yesterday use from a private seller and for both of us it was our first time doing A private sale . I should have done more research about buying a used car from a private seller . Now that I have the car and the title and I have paid him the money he propose that I get the car smog right away and he will pay for it but will the DMV except this? Since the smog test will be on a date after the purchase date?

  4. I sold a car (to family.. Big mistake) and did not get it smogged I have messages that the buyer knew The car was not smoged and that they would take care of it. They have had the car for 2weeks and have done nothing (no DMV paperwork and no smog), since I have contact with them I have texted them once a week in regards to this and they tell me they will tale care of it and never do. I have also within these messages have asked how the car was to which their reply was great. They now tell me the car check engine light is on and we need to fix it. I agree and tell them it will take a week and a half to do (it will take 4 days to just order the part . )They do not like the time frame and are now demanding their money back or they will sue. They have had the car for two weeks already! Since I as the seller an taking responsibility and offering to fix it and they won’t comply what do I do?

    • What kind of family are you talking about here, immediate family or distant relatives? Immediate family members can transfer ownership of a vehicle without a smog being required. That’s just for transferring it, but if it’s due for is biennial smog check than yes it would need to be smogged.

  5. So if I buy a used car from a private party and the smog was done prior to the sale and they provided me with said smog cert. and then I went and had it smogged and it failed who is responsible

  6. Thanks for the info. What could potentially happens to the seller in this situation if neither party knew about the 90 days smog law?

  7. Thank you for your post.
    So, I bought a used G35 for my son in 2016. the first year,2017, we did not need a smog, but now we need a smog and the test stations will not take the vehicle to test as it has a modify intake system. Which we had no idea that even would matter (I’m so mad!). Now we know because we requested a EO Decal, but they will not issue one because intake system you have installed has not received exemption for your specific application from C.A.R.B. (who knew). I’ve tried calling back the used car dealership for the last couple days, and of course, total avoidance. Now that I’m thinking about it, they probably switched the intake system to pass it. What are my rights? Can I file a claim, maybe with BBB? Now we have to buy an original intake system which is $231 plus and then labor. Please let me know any thoughts you may have. Thank you!

  8. I have a 2006 Dodge Caravan that was involved in a minor wreck a couple years ago, and sustained some front end damage. The car’s been sitting for two years. I started fixing it, but just want to sell it now because I need the space. The problem is, the battery went dead while it was sitting, and the computer lost its memory, so it’s no longer in an “IM Ready” state, meaning it won’t pass a smog test, even if it tests okay, until the computer resets everything. From past experience, I know that it takes at least a couple hundred miles of driving for all those sensors to reset, so I can’t get it smogged when I sell it. I did file a PNO with the DMV a year or two ago, and I know its always passed smog with no problems (74,200 miles on the odometer). The battery is now charged, and the car runs just fine but again, I’d have to drive it around for quite some time to reset the computer, and I don’t want to pay to register it, since I’ll probably only get $1000 for it anyway. Can I make a full written disclosure, and state that the car is being sold as is for parts, and that it is up to the buyer to decide whether he wants to smog and register it, or just part it out?

  9. What if I am trying to sell a car that is registered out of state? Though it is not CA registered, does it’s still need to pass smog to be sold in CA?

    • Did anyone find an answer to this?

    • C’mon really. Look it up James. Nobody is going to know that answer off top of their head.

  10. I bought a car 6 days ago the seller give me the smog certificate I drove the car less than 100 miles and I realized that the car was having a problem running then the check engine light show up I connected to the scanner and find out that there was a code,
    I believe the seller erase the codes give me a illegal smog certificate and now I am stuck with the car, so I call the person and he didn’t pic up the phone.
    What should I do now?
    Any legal action that I can take?

  11. I bought a 2011 Mercedes sprinter from a used car dealer. After signing all paperwork and paying cash for the van I was informed it was not smogged. He said I can take or his guy could do it, did not trust his guy obliviously. since purchase check engine came on twice second one has not gone away and it was passed 30 day warranty. I paid registration fees with purchase. Basically I now have a van that cannot be driven in ca legally.

    • Take it back to the dealership. They cannot legally put any vehicle on their lot for sale unless it has been smogged and passed. It’s their responsibility, not yours.

  12. I bought a used car from a dealership in Inglewood and one week after I bought it I found out it has two several oil leaks, then I get on the phone with the dealership who sold it to me and they refuse to acknowledge is their full responsibility to pay for the repairs. Total amount of the repairs is half the price of the car which the dealership claims is on me because I bought it “as is”. I dont know what to do at this point or where to get help from..

  13. Can you register your car as PNO and legally sell it that way without a smog cert in CA? Selling car and buyer understands it needs a repair and currently wouldn’t pass smog.

  14. First of all, thank you for posting this as this is a confusing topic. I bought a car one year ago and the seller had the car smogged. I have the paperwork to prove it. My question concerns the fact that I received my renewal notice from the DMV and it says “Smog certification required at a STAR station”. Being as I live in Alameda County with biennial smog requirements, why am I being told to smog my car again?

  15. My son bought his first car off of craigslist. He didn’t check the date on the smog certificate they gave him and as he was driving away the check engine light came on. His efforts to contact the seller went unanswered. He has a car he hasn’t been able to register in his name because it won’t pass smog. At this point he just wants to sell it, but I don’t know if he can.


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