Price
Call for price
Hours
Open 7 days a week
Station type
Test & Repair
Appointments
Walk-ins welcome
Hours
- Monday
- 12 AM – 12 PM
- Tuesday
- 12 AM – 12 PM
- Wednesday
- 12 AM – 12 PM
- Thursday
- 12 AM – 12 PM
- Friday
- 12 AM – 12 PM
- Saturday
- 12 AM – 12 PM
- Sunday
- 12 AM – 12 PM
Good to know
Languages
English
Payment
Credit Card, Debit Card, NFC/Contactless
What to expect at Four Corners Union
Four Corners Union is licensed by the Bureau of Automotive Repair as a Test & Repair smog station in Concord, so it can run the inspection and, if your car fails, diagnose and fix it in the same shop. It is STAR certified, so it can test vehicles the DMV directs to a STAR station, including gross polluters.
Walk-ins are welcome. Most smog checks take 15 to 30 minutes, and most visits are closer to 20.
What to bring
Your registration or DMV renewal notice
It says whether the car needs a STAR station.
The car, with the check engine light off
On a 2000-or-newer car, a lit check engine light fails the test on its own.
A way to pay
The $8.25 state certificate is paid on top of the test when the car passes, unless the station's price or coupon includes it.
What if I fail?
- Four Corners Union can diagnose and repair the problem in the same shop, then retest the car.
- Each station sets its own retest price, so ask before the first test.
- BAR's Consumer Assistance Program pays up to $1,450 toward emissions repairs for income-eligible owners.
2025 Monument Blvd, Concord, CA 94520
Get directions →Hours
- Monday
- 12 AM – 12 PM
- Tuesday
- 12 AM – 12 PM
- Wednesday
- 12 AM – 12 PM
- Thursday
- 12 AM – 12 PM
- Friday
- 12 AM – 12 PM
- Saturday
- 12 AM – 12 PM
- Sunday
- 12 AM – 12 PM
Also listed on
Other stations near Four Corners Union
Nearby cities in Contra Costa County
Questions about Four Corners Union
Four Corners Union is open Monday 12 AM to 12 PM; Tuesday 12 AM to 12 PM; Wednesday 12 AM to 12 PM; Thursday 12 AM to 12 PM; Friday 12 AM to 12 PM; Saturday 12 AM to 12 PM; Sunday 12 AM to 12 PM. Hours can change on holidays, so call ahead if you are cutting it close.
Four Corners Union accepts Credit Card, Debit Card, NFC/Contactless.
Google lists the following accessibility features at Four Corners Union: wheelchair accessible restroom.
Four Corners Union has held a BAR smog license since 2004. You can verify the license status at bar.ca.gov.
Four Corners Union has not published a price on SmogCheckDeals. The Bureau of Automotive Repair puts the statewide average at $69.16 as of August 2026, about $65 for a 2000-or-newer vehicle and $73 for 1999-or-older, plus the $8.25 certificate fee. Call (925) 682-3142 for a quote.
Four Corners Union does not take online bookings here, but walk-ins are welcome. Call (925) 682-3142 to check the wait.
Staff at Four Corners Union speak English.
The closest alternatives in Concord are Auto Smog Center (0.2 mi) and Concord Smog Tune & Brakes (0.4 mi). Both are listed further up this page with their ratings and hours.
How we get this data: BAR licenses and STAR status, Google hours and ratings, coupons published by the station.
Verify this station’s license and STAR standing at bar.ca.gov.
Own this shop? Add photos
BAR field office: Hercules • Licensed since 2004