JO Clean Truck Check

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

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

Location
2021 Woodland Ave, Modesto, CA 95358
County
Stanislaus County
Phone
(209) 326-8839
Mobile testing
Yes — comes to your yard
OBD testing
Yes
Smoke opacity (non-OBD)
Yes
Motorhomes
No
Credentialed testers
1
Last verified

Call (209) 326-8839 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 JO Clean Truck Check can test

The test CARB requires depends on the engine's fuel and model year. Based on the services JO Clean Truck Check 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 yearNot listed

Clean Truck Check testers in Stanislaus County

JO Clean Truck Check 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 Modesto itself there are 23 listed businesses, 21 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 JO Clean Truck Check 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 JO Clean Truck Check offer mobile Clean Truck Check testing?

Yes. JO Clean Truck Check 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 JO Clean Truck Check test a 2012 or older diesel truck?

Yes. JO Clean Truck Check 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 JO Clean Truck Check charge for a Clean Truck Check?

JO Clean Truck Check has not published prices with us; call (209) 326-8839 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 JO Clean Truck Check a CARB-credentialed tester?

JO Clean Truck Check 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 Modesto

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) 326-8839