What a smog check referee does and when you need one
A smog check referee is a state-certified inspector who re-tests your vehicle when you have failed an initial smog check. You do not go to a referee automatically — you only visit one if your car failed the test at a regular smog station and you believe the failure was wrong, or if you have made repairs and want to retest before paying for a new smog check.
The referee inspection costs less than a regular smog check (typically $30 to $50 versus $50 to $100) and is your chance to verify the results. Referees work for the Bureau of Automotive Repair, a division of California's Department of Consumer Affairs, so they are independent of the station that failed your vehicle.
You have 30 days from the date of your failed test to visit a referee. After 30 days, you must pay for a new smog check at a regular station. If you pass the referee inspection, that result counts as your official smog check — you do not need to test again.
Key Takeaways
- Referee inspections are free to request and cost $30 to $50, compared to $50 to $100 for a regular smog check.
- You must visit a referee within 30 days of your failed test, or you will need to pay for a new smog check at a regular station.
- The Bureau of Automotive Repair maintains a searchable list of referee stations on its website, organized by county.
- Bring your failed smog check report, vehicle registration, and proof of any repairs you have made since the failure.
- If you pass the referee test, that result is your official smog check and you do not need to test again.
How to find a referee station near you
The Bureau of Automotive Repair publishes a searchable database of all licensed referee stations on its website at bar.ca.gov. Go to the "Find a Smog Check Station" tool, select "Referee" from the station type dropdown, and enter your county or ZIP code. The results show each referee's address, phone number, and hours.
Referee stations are typically independent repair shops, not the same station where you failed your test. Calling ahead is a good idea — some referees have limited hours or may be booked several days out. Tell them you have a failed smog check report and want to schedule a retest.
You do not need an appointment at most referee stations, but calling first saves you a wasted trip. Some referees will ask you to bring your failed report when you call so they can note the specific emissions readings that failed.
What to bring to your referee inspection
Bring your original failed smog check report, your vehicle registration, and your driver's license. The referee needs the failed report to compare your new test results against the previous ones and to document the retest in the state system.
If you have had repairs done since the failure, bring receipts or a work order showing what was fixed. You do not have to prove the repairs worked — the referee will test your vehicle — but documentation helps the referee understand what you addressed. Common repairs that affect smog results include oxygen sensor replacement, catalytic converter work, or engine control computer updates.
If you have not made repairs and are retesting the same vehicle without changes, that is also fine. The referee will test it as-is. Some vehicles fail due to testing error or temporary conditions, and a second test may show different results.
What happens during a referee inspection
The referee inspection is the same test as a regular smog check — your vehicle is connected to an emissions analyzer that measures exhaust gases. The test takes 10 to 15 minutes. The referee will check your vehicle's onboard diagnostic system and run the tailpipe emissions test, just as the original station did.
The referee is looking at the same standards your vehicle must meet. If your car passes, the referee prints a new smog check certificate and submits it to the state. If your car fails again, the referee will give you a new failed report showing which emissions exceeded the limit. You then have the choice to make repairs and return to any smog station (not necessarily a referee) for a new test, or to visit another referee within 30 days of this new failure.
The referee will not tell you what is wrong with your vehicle or recommend repairs. That is outside the scope of a referee inspection. If you need diagnostic work, you will need to take your vehicle to a repair shop separately.
When a referee inspection makes sense versus a new regular test
A referee inspection is worth the trip if you believe the first test was inaccurate, or if you have made repairs and want to confirm they worked before paying for a full new smog check. Because referees are independent and cost less, they are a reasonable second opinion.
A referee inspection does not make sense if your vehicle genuinely needs repairs. If your car failed because of a real emissions problem — a bad oxygen sensor, a failing catalytic converter, or a check engine light — you need a repair shop, not a retest. Visiting a referee will only confirm the same failure and waste the $30 to $50 fee.
If you are past the 30-day window from your original failure, you cannot use a referee. You must pay for a new smog check at a regular station. The 30-day clock resets from the date of that new test if you fail again.
What to do if you fail the referee inspection
If you fail at the referee station, you have two paths. You can take your vehicle to a repair shop to diagnose and fix the emissions problem, then return to any smog station (regular or referee) for a new test. Or, if you are still within 30 days of your original failed test, you can visit a different referee station for a second opinion.
Keep in mind that visiting multiple referees does not change the underlying problem — if your vehicle is emitting too much, it will fail at any certified station. The value of a second referee visit is only if you suspect the first referee's equipment was faulty or the test was run incorrectly, which is rare.
After you have repairs done, you do not have to return to the same station. Any smog station can test your vehicle. Some people prefer to return to a referee for the retest after repairs, since referees cost less, though a regular station works just as well.
Understanding your failed smog check report
Your failed smog check report shows which emissions exceeded the state limit. Most reports list nitrogen oxides (NOx), hydrocarbons (HC), carbon monoxide (CO), or a combination. The report also shows your vehicle's model year and engine type, because standards vary by year and engine.
The report may also note whether your vehicle's check engine light is on. A lit check engine light does not automatically fail a smog test, but it can indicate an emissions problem that will show up in the test results. If the light is on, a repair shop can read the diagnostic code to identify the issue.
Bring this report to the referee so they can see exactly what failed and compare the new test results. The referee will not explain what caused the failure — that requires a diagnostic scan at a repair shop — but the report itself tells you which system to focus on if you decide to pursue repairs.
Frequently Asked Questions
Can I dispute a smog check failure without visiting a referee?
No. A referee inspection is the only formal way to challenge a smog check result. If you believe the test was wrong, you must visit a referee within 30 days. After 30 days, you can only get a new test by paying for a fresh smog check at a regular station.
Do I have to go back to the same station that failed me?
No. You can visit any referee station in the state. Most people choose one near their home or work for convenience. The referee is independent of the original station and has no connection to the first test.
What if I pass the referee inspection — do I still need a regular smog check?
No. A passing referee inspection counts as your official smog check. You do not need to test again. The referee submits the passing result to the state, and you can use that certificate for registration renewal or sale of the vehicle.
How long does a referee inspection take?
The test itself takes 10 to 15 minutes. Wait time depends on how busy the referee station is. Some stations take walk-ins and you may wait 30 minutes to an hour; others require appointments and you go straight in. Calling ahead tells you what to expect.
Can a referee station refuse to test my vehicle?
Yes. A referee can refuse to test a vehicle that is unsafe to drive — for example, if the brakes are not working or the vehicle is leaking fluid. The referee can also refuse if your vehicle is so heavily modified that it does not match the registration. In either case, you would need to address the safety issue or get the vehicle back to stock before testing anywhere.