JB Mobile Service

Clean Truck Check tester in Napa, CA (Napa County).

JB Mobile Service 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
787 Airpark Rd, Napa, CA 94558
County
Napa County
Phone
(707) 206-5358
Mobile testing
Yes — comes to your yard
OBD testing
Yes
Smoke opacity (non-OBD)
Yes
Motorhomes
No
Credentialed testers
1
Last verified

Call (707) 206-5358 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 JB Mobile Service can test

The test CARB requires depends on the engine's fuel and model year. Based on the services JB Mobile Service 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 Napa County

JB Mobile Service is one of 11 testing businesses in Napa County on CARB's public tester list. 11 of them offer mobile testing and 6 do smoke opacity tests. In Napa itself there are 11 listed businesses, 11 of them mobile. All testers in Napa 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 JB Mobile Service 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 JB Mobile Service offer mobile Clean Truck Check testing?

Yes. JB Mobile Service 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 JB Mobile Service test a 2012 or older diesel truck?

Yes. JB Mobile Service 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 JB Mobile Service charge for a Clean Truck Check?

JB Mobile Service has not published prices with us; call (707) 206-5358 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 JB Mobile Service a CARB-credentialed tester?

JB Mobile Service 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 Napa

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 (707) 206-5358