Diesel Air Defense
Clean Truck Check tester in Tracy, CA (San Joaquin County).
- Mobile testing
- OBD test
- Motorhomes
Diesel Air Defense appears on CARB's public list of credentialed Clean Truck Check testers. It lists mobile testing, OBD testing, motorhome testing. Mobile testing means the tester can come to your yard or job site.
- Location
- 201 S 3rd St, Tracy, CA 95376
- County
- San Joaquin County
- Phone
- (209) 507-9103
- Mobile testing
- Yes — comes to your yard
- OBD testing
- Yes
- Smoke opacity (non-OBD)
- No
- Motorhomes
- Yes
- Credentialed testers
- 1
- Last verified
Call (209) 507-9103 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 Diesel Air Defense can test
The test CARB requires depends on the engine's fuel and model year. Based on the services Diesel Air Defense lists on CARB's tester list:
| Your vehicle | Test required | This tester |
|---|---|---|
| Diesel, model year 2013 or newer | OBD scan | Yes |
| Alternative fuel (natural gas, propane), 2018 or newer | OBD scan | Yes |
| Diesel, model year 2012 or older (no OBD) | Smoke opacity test (SAE J1667) plus visual inspection | Not listed |
| California-registered motorhome | Same test as above by engine year, once a year | Yes |
For a 2012 or older diesel, the nearest listed tester with smoke opacity testing is Christine's Mobile CTCT in Tracy, about 1 mile away. See listing.
Clean Truck Check testers in San Joaquin County
Diesel Air Defense is one of 124 testing businesses in San Joaquin County on CARB's public tester list. 111 of them offer mobile testing and 53 do smoke opacity tests. In Tracy itself there are 21 listed businesses, 20 of them mobile. All testers in San Joaquin 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 Diesel Air Defense 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 Diesel Air Defense offer mobile Clean Truck Check testing?
Yes. Diesel Air Defense 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 Diesel Air Defense test a 2012 or older diesel truck?
Diesel Air Defense does not list smoke opacity testing, which older non-OBD diesel trucks need. The nearest listed tester that does is Christine's Mobile CTCT (about 1 mile). Trucks from 2013 on get an OBD scan instead.
How much does Diesel Air Defense charge for a Clean Truck Check?
Diesel Air Defense has not published prices with us; call (209) 507-9103 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 Diesel Air Defense a CARB-credentialed tester?
Diesel Air Defense 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 Tracy
-
Christine's Mobile CTCT
- Mobile testing
- OBD test
- Smoke opacity
- Motorhomes
-
Joe's Smog Shack Inc.
- OBD test
- Motorhomes
-
Plugnpass LLC
- Mobile testing
- OBD test
-
Rakesh reddy Boja
- Mobile testing
- OBD test
- Smoke opacity
-
Sandhu Truck Services
- Mobile testing
- OBD test
- Motorhomes
-
Speedee Oil Change
- Mobile testing
- OBD test
- Motorhomes
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.