What to Bring to a Smog Check (and What Happens During the Test)
For a California smog check, bring the car, your DMV renewal notice if you have one, and a way to pay. You do not need to bring paperwork to the DMV afterward: when the car passes, the station sends the smog certificate to the DMV electronically. A typical test of a 2000-or-newer car takes 20 to 30 minutes.
What to bring
- The vehicle, warmed up from at least 20 minutes of driving.
- DMV renewal notice, which shows whether a STAR station is required.
- Payment for the test and the $8.25 state certificate fee if it is charged separately.
- Wheel lock key if your car needs to go on a dynamometer.
What the technician checks
| Part of the test | What happens |
|---|---|
| Visual inspection | Required emissions parts are present, connected and California-approved |
| Functional checks | Check engine light, gas cap or fuel-evaporative system, and on some cars ignition timing and EGR |
| OBD II scan (most 2000-and-newer cars) | Fault codes and readiness monitors |
| Tailpipe test (older cars) | Exhaust gases measured, on rollers or at idle |
Book a station
- Smog check in San Jose — 2 listings
- Smog check in Anaheim — 1 listing
- Smog check in Los Angeles — 1 listing
- Smog check in Sacramento — 1 listing
- Smog check in San Diego — 1 listing
- Smog check in San Francisco — 1 listing
- Smog check in Santa Clara — 1 listing
- Smog check in Sunnyvale — 1 listing
Frequently asked questions
Do I need my registration card for a smog check?
It helps but is not usually required. The station identifies the car by its VIN and license plate. The renewal notice tells the station whether you need a STAR test.
Can someone else take my car for a smog check?
Yes. The registered owner does not have to be present.
Do I get a paper smog certificate?
The certificate is sent to the DMV electronically. You get a Vehicle Inspection Report as your receipt.
How long does a smog check take?
Usually 20 to 30 minutes for a car built in 2000 or later, where the test reads the on-board diagnostics (OBD) system. Older vehicles get a tailpipe test that can take longer.
Related guides
- How to Pass a California Smog Check: 10 Checks Before You Go — A practical pre-test checklist: check engine light, readiness monitors, gas cap, oil change, warm engine and the mistakes that make good cars fail.
- STAR vs Regular Smog Check: Which One Do You Need? — Your DMV renewal notice tells you whether you need a STAR station. What STAR means, why cars get selected, and how to find a STAR station near you.
- How Much Does a California Smog Check Cost? (2026) — Smog check prices are set by each station, plus a fixed $8.25 state certificate fee. What changes the price, who is exempt and what happens if you fail.