Clean Truck Check testers in Walnut, CA

3 testing businesses in Walnut are on CARB's public Clean Truck Check tester list (4 credentialed testers). 3 offer mobile testing at your yard, 1 can do smoke opacity tests for older non-OBD trucks and 3 test motorhomes. Counting nearby cities, 385 listings are within 20 miles.

Testers in Walnut

More testers within 20 miles of Walnut

Trucking in Walnut: what to know

Los Angeles County has more listed testers than any other county. Seaports and intermodal railyards, including the Ports of Los Angeles and Long Beach, must verify Clean Truck Check compliance at entry or log non-compliant trucks (CARB).

What a Clean Truck Check costs in Walnut

Testers set their own prices and most do not publish them. Across the California prices we found, an OBD test usually costs $50–$135 per vehicle and a smoke opacity test $190–$200. Mobile testers in Walnut may add a trip fee but often discount fleets that test several trucks at once. How prices compare.

Frequently asked questions

How many Clean Truck Check testers are in Walnut?

CTC Finder lists 3 testing businesses in Walnut from CARB's public tester list (4 credentialed testers), last checked November 1, 2026. Listing on CARB's list is optional, so the real number can be higher.

Is there mobile Clean Truck Check testing in Walnut?

Yes. 3 listed businesses in Walnut offer mobile testing, which means the tester comes to your yard. Use the Mobile filter above to see them.

How much does a Clean Truck Check test cost in Walnut?

Testers set their own prices. Published prices for an OBD test are usually $50–$135 per vehicle; smoke opacity tests for older trucks often cost more, and mobile testers may add a trip fee. See the cost guide.

How often does my truck need a Clean Truck Check test?

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.

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.