Ace smog

Clean Truck Check tester in Ceres, CA (Stanislaus County).

Ace smog appears on CARB's public list of credentialed Clean Truck Check testers. It lists mobile testing, OBD testing, smoke opacity (non-OBD) testing, motorhome testing. Mobile testing means the tester can come to your yard or job site.

Location
2500 Mary Ave, Ceres, CA 95307
County
Stanislaus County
Phone
(209) 531-6823
Mobile testing
Yes — comes to your yard
OBD testing
Yes
Smoke opacity (non-OBD)
Yes
Motorhomes
Yes
Credentialed testers
1
Last verified

Call (209) 531-6823 Open in Google Maps

Before you call

  • Have your VIN, odometer reading and plate number ready.
  • Your vehicle must be registered in CTC-VIS and the annual compliance fee paid; the tester submits the result to CARB.
  • Ask for the price per vehicle and any mobile trip fee. Typical published prices for an OBD test are $50–$135 per vehicle (see cost guide).

Which trucks Ace smog can test

The test CARB requires depends on the engine's fuel and model year. Based on the services Ace smog lists on CARB's tester list:

Your vehicleTest requiredThis tester
Diesel, model year 2013 or newerOBD scanYes
Alternative fuel (natural gas, propane), 2018 or newerOBD scanYes
Diesel, model year 2012 or older (no OBD)Smoke opacity test (SAE J1667) plus visual inspectionYes
California-registered motorhomeSame test as above by engine year, once a yearYes

Clean Truck Check testers in Stanislaus County

Ace smog is one of 53 testing businesses in Stanislaus County on CARB's public tester list. 47 of them offer mobile testing and 22 do smoke opacity tests. In Ceres itself there are 7 listed businesses, 6 of them mobile. All testers in Stanislaus County.

When your truck is due

Most trucks test twice a year, on a schedule tied to the DMV registration expiration date. CARB says OBD trucks move to four tests a year beginning October 2027. California-registered (non-commercial) motorhomes and agricultural vehicles test once a year. See the deadline guide. You can test up to 90 days before a deadline. Get a free email reminder before each one.

How to check a tester's credential

CARB publishes its Clean Truck Check tester list, where Ace smog appears as of November 1, 2026. Listing there is optional, so a missing name does not always mean a tester is not credentialed. After the test, check that the passing result shows for your vehicle in CTC-VIS; that is what counts for compliance.

Frequently asked questions

Does Ace smog offer mobile Clean Truck Check testing?

Yes. Ace smog says on CARB's tester list that it offers mobile testing, so it can come to your yard or job site. Ask about a trip fee when you call.

Can Ace smog test a 2012 or older diesel truck?

Yes. Ace smog lists smoke opacity testing, the test CARB requires for diesel trucks of model year 2012 and older (no OBD). See OBD vs smoke opacity.

How much does Ace smog charge for a Clean Truck Check?

Ace smog has not published prices with us; call (209) 531-6823 for a quote. Published California prices are usually $50–$135 per vehicle for an OBD test and $190–$200 for a smoke opacity test, plus CARB's annual fee ($32.13 in 2026). See the cost guide.

Is Ace smog a CARB-credentialed tester?

Ace smog appears on CARB's public Clean Truck Check tester list, last checked November 1, 2026. Only credentialed testers can submit results to CARB; after the test, confirm the passing result shows for your vehicle in CTC-VIS.

Other testers near Ceres

Source: CARB's public Clean Truck Check tester list, last checked . Listing on CARB's list is optional for testers, so some credentialed testers are not shown. Services, hours and prices change; please confirm with the tester before you go. Something wrong? Send a correction.

Call (209) 531-6823