What a smog check history record shows
Your California smog check history is a record of every emissions test your vehicle has passed or failed, kept by the state's Bureau of Automotive Repair. When you take a vehicle for a smog test, the test station reports the results to a central database. That record stays there permanently — you can look up any test from the past, whether it passed or failed, and see the date, location, and which station performed it.
The history shows the test result itself (pass or fail), the vehicle's odometer reading at the time of the test, the test station's name and number, and the date the test was completed. If a test failed, the record includes which emissions systems did not meet state standards. This history matters because California law requires proof of a passing smog test before you can register or renew registration for most vehicles, and lenders or buyers may ask to see it.
Key Takeaways
- California keeps a permanent record of every smog test result in a state database that you can search by vehicle license plate or VIN.
- You can look up your own smog history free through the Bureau of Automotive Repair website without needing to contact the test station.
- A passing smog test is valid for 30 days before you must register the vehicle; if registration lapses, you will need a new test.
- If your vehicle failed a test, the record shows which emissions systems failed, and you can retake the test at any station after repairs are made.
- Smog test records are public information, but only you, your mechanic, or someone with written permission can request your specific vehicle's history.
How to look up your vehicle's smog test record
Go to the Bureau of Automotive Repair's online search tool at bar.ca.gov and select "Smog Check Program" from the main menu. You will find a link to the "Smog Check History" lookup. Enter your vehicle's license plate number or Vehicle Identification Number (VIN) — either one works. The system will display every test on record for that vehicle, with the most recent test listed first.
The search is free and does not require you to log in or create an account. Results appear when ready. If no tests appear, either the vehicle has never been tested in California or the plate number or VIN was entered incorrectly. Double-check the VIN on your registration or title document, as even one wrong digit will return no results.
If you cannot access the website or need a certified copy of your smog history for a lender or buyer, you can call the Bureau of Automotive Repair at 1-800-952-5210 and request a printout by mail. They will mail you an official record within one to two weeks. There is no charge for this service.
What happens if your vehicle failed a smog test
A failed test stays in your history permanently, but it does not prevent you from registering the vehicle — you straightforward need to pass a new test before registration is complete. The failed test record shows which specific emissions systems did not meet standards: typically the oxygen sensor, catalytic converter, fuel system, or engine control computer.
After a failed test, you can take your vehicle to any mechanic or smog station for repairs. You do not have to return to the same station that performed the failed test. Once repairs are complete, you can retake the smog test at any station. There is no waiting period between a failed test and a retest, though some stations may charge a retest fee (usually $20 to $40).
If you retake the test and pass, the new passing result appears in your history alongside the failed test. Both records remain visible. When you register your vehicle, California will accept the most recent passing test, regardless of how many failed tests came before it.
How long a passing smog test remains valid
A passing smog test is valid for 30 days from the test date. You must complete vehicle registration within that 30-day window. If you do not register within 30 days, the test expires and you will need a new smog test before you can register.
Once your vehicle is registered, you do not need another smog test until your registration renewal comes due. California requires a smog test every two years for most vehicles, though some newer vehicles (typically 2000 and newer) may be exempt depending on the model year and whether the vehicle has been modified. Your registration renewal notice will tell you whether a smog test is required.
If your registration lapses — meaning you do not renew it before the expiration date — you will need a new smog test to reinstate it, even if your previous test was recent. The test date on your registration renewal paperwork is what matters, not the date of your last test.
Understanding test results and emissions standards
A smog test measures how much nitrogen oxide, carbon monoxide, and particulate matter your vehicle's exhaust contains. California's standards are stricter than federal standards. The test station compares your vehicle's emissions to the limit for your vehicle's model year and engine type. If all measurements fall below the limit, the test passes. If any measurement exceeds the limit, the test fails.
Your smog history record will show the actual emissions readings if the test failed, along with the allowable limit for your vehicle. This information helps a mechanic understand what system needs repair. For example, if carbon monoxide is high, the problem is usually a rich fuel mixture (too much fuel, not enough air). If nitrogen oxide is high, the oxygen sensor or catalytic converter may be failing.
Passing tests do not show the actual emissions numbers — only that all readings were within limits. This is why a passing test does not tell you how close your vehicle came to failing.
Who can see your smog check history
Smog test records are public information in California, but access is controlled. You can always look up your own vehicle's history using the Bureau of Automotive Repair website. A mechanic or smog station can look up your history if you provide your license plate or VIN in person. A potential buyer or lender can request your history if you give them written permission and your vehicle's plate or VIN.
The Bureau of Automotive Repair will not release your history to anyone else without a court order. If someone claims they need your smog history but you did not give permission, you can contact the bureau to report the request. The bureau's consumer complaint line is 1-800-952-5210.
What to do if your smog history shows an error
If you believe a test result in your history is wrong — for example, if you never took a test that appears in the record, or if a passing test is listed as a failure — contact the test station that performed the test first. The station can review their records and request a correction from the Bureau of Automotive Repair if an error occurred.
If the test station does not respond or denies there was an error, contact the Bureau of Automotive Repair directly at 1-800-952-5210 with your vehicle's plate or VIN and the date of the disputed test. Provide any documentation you have, such as receipts from repairs or registration paperwork. The bureau will investigate and correct the record if an error is found. This process typically takes two to four weeks.
Frequently Asked Questions
Can I see someone else's smog check history?
Only if they give you written permission and their vehicle's license plate or VIN. You can look up any vehicle's history using the Bureau of Automotive Repair website, but the results are considered private information. A buyer or lender may ask you to provide your own history as proof of a passing test.
How far back does smog check history go?
California keeps smog test records indefinitely. You can look up tests from 10, 20, or 30 years ago if they are in the system. However, the Bureau of Automotive Repair's online search tool typically displays the most recent 10 years of tests. If you need older records, call 1-800-952-5210 and request a full history by mail.
What if I bought a used car and the seller did not provide a smog test?
You can look up the vehicle's smog history yourself using the license plate or VIN on the Bureau of Automotive Repair website. This shows you whether the vehicle passed its most recent test and when. If no recent passing test appears, you will need to obtain one before you can register the vehicle in your name.
Does a smog test history affect my vehicle's resale value?
A smog history itself does not affect value, but multiple failed tests may signal to a buyer that the vehicle has ongoing emissions problems. A single failed test followed by a pass shows the problem was repaired. Buyers often request smog history to understand the vehicle's maintenance record and emissions compliance.
Can I get a smog test waived if my vehicle is very old?
California has exemptions for vehicles older than 1975 and some vehicles between 1975 and 1980, depending on the model year and engine type. Your registration renewal notice will state whether a smog test is required. If you believe your vehicle should be exempt, contact the Bureau of Automotive Repair at 1-800-952-5210 with your vehicle's VIN and registration information.