Short answer: Yes, an OBD truck (diesel 2013 and newer, alternative fuel 2018 and newer) can pass Clean Truck Check without a shop visit, but the test still has to be done by a CARB-credentialed tester with a CARB-certified OBD test device. There are three ways: a mobile tester comes to your yard with a handheld scan tool, a telematics device that CARB has certified stays plugged into the truck and runs the tests, or a remote service where a credentialed tester supervises the test with a device sent to you. CARB lists 8 certified telematics ("continuously connected") device approvals from 6 companies: Geotab, Samsara, Motive, Zonar, Verizon Connect and Pacific Track. Smoke opacity tests for diesel 2012 and older cannot be done remotely.
The three ways to test an OBD truck without a shop
| Option | How it works | Good for | Watch out for |
|---|---|---|---|
| Mobile tester | A credentialed tester drives to your yard and plugs a certified scan tool into each truck. | One truck to a large fleet; no hardware to buy. | Trip fee for a single truck; book ahead before deadlines. |
| Certified telematics device (continuously connected) | A CARB-certified device stays in the truck. Tests are uploaded to CARB automatically when the device belongs to a credentialed tester. | Fleets that already run Geotab, Samsara, Motive, Zonar, Verizon Connect or Pacific Track. | Not every device model is certified; a credentialed tester must be tied to the device. |
| Remote service ("test from your phone") | A testing business ships or installs a certified device and a credentialed tester runs and submits the test remotely. | Owner-operators far from testers, out-of-state trucks. | Check the business is credentialed and the device is on CARB's list before paying. |
From October 2027, OBD trucks test four times a year instead of twice (what changes in 2027). That makes a telematics device or a standing arrangement with a mobile tester more attractive for fleets.
What CARB actually requires
- A certified device. CARB says only CARB-certified OBD test devices can be used for periodic compliance tests. Its device list has two groups: NCC (non-continuously connected) scan tools used on many vehicles, and CC (continuously connected) telematics devices assigned to one vehicle.
- A credentialed tester. A test is rejected if the tester did not have valid credentials when the test was scanned. Owners can test their own trucks only if they are credentialed themselves (become a tester).
- Automatic upload only for testers' telematics. CARB's FAQ says OBD tests are automatically uploaded only for the telematics devices of credentialed testers. Having a fleet telematics box in the truck is not enough by itself.
- The vehicle must still be compliant in CTC-VIS. The truck must be reported in CTC-VIS with the annual fee paid ($32.13 in 2026). A passing test alone does not produce a compliance certificate.
CARB-certified telematics (continuously connected) devices
CARB's OBD test device page lists these continuously connected approvals:
| Company | Device families on CARB's list |
|---|---|
| Geotab | GO9, GO9B, GO9+ |
| Samsara | VG-55, VG54-NA, VG54-NAH, VG34 (two approvals) |
| Motive | Motive Vehicle Gateway LBB-3.55CA, LBB-3.6CA |
| Zonar | V4 and VT4 (two approvals) |
| Verizon Connect | Xirgo XT6372R, XT6383 |
| Pacific Track | PT40, PT40-Q |
CARB notes that resellers and telematics providers may sell these devices under other brand names. Ask your provider for proof of certification: the CARB Executive Order (EO) number for your exact device.
Certified handheld scan tools (used by mobile and shop testers) come from RA Consulting (Silver Snap-Tool), DG Technologies (DPA INSPECT), Noregon (Truck Check Up), HEM Data (DAWN OBD Inspector) and Opus (Clean Truck kit).
Before you pay a remote or telematics service: 6 questions
- Is the business on CARB's credentialed tester list? Look it up on our tester directory or CARB's list. Listing is optional, so also ask for the tester's 8-character CARB tester ID.
- Which device, and what is its CARB EO number? Compare it with CARB's device page.
- Who submits the result to CARB, and how fast? You should see the test in your CTC-VIS account.
- Is it per test or a subscription? With four tests a year from October 2027, compare the yearly cost with a mobile tester's price.
- What happens if the truck fails? Ask whether a retest after repair is included.
- Does it cover all my trucks? Remote and telematics options only work for OBD trucks; diesel 2012 and older still need a smoke opacity test in person.
Prefer a person at your yard? 2,543 of the 2,867 testing businesses we list in California offer mobile testing, or get quotes from up to 3 testers for your fleet.
Sources
- CARB, Clean Truck Check OBD test devices (CC and NCC device lists)
- CARB, Clean Truck Check FAQ (automatic upload, self-testing, quarterly testing)
- CARB, Clean Truck Check test results FAQ (tester credentials, physically connected device)
- CARB, Requirements for vehicles subject to semi-annual compliance
Frequently asked questions
Can I do a Clean Truck Check from my phone?
Not by yourself with an app alone. The test must be run by a CARB-credentialed tester with a CARB-certified OBD device connected to the truck. Some testing businesses offer remote tests where they provide the device and submit the result for you.
Does my Samsara, Geotab or Motive device count as a Clean Truck Check test?
Only if the exact device model is CARB-certified and the test is tied to a credentialed tester. CARB says OBD tests are uploaded automatically only for telematics devices of credentialed testers. Ask your provider for the CARB Executive Order number and how they handle the tester credential.
Can older trucks be tested remotely?
No. Diesel trucks 2012 and older need a smoke opacity test (SAE J1667) with a visual inspection, and alternative-fuel trucks 2017 and older need a visual inspection. Both need a tester on site.
Is remote testing cheaper than a mobile tester?
It depends on the number of trucks and tests. Published mobile OBD prices are usually $50–$135 per truck per test. Remote and telematics services often charge per test or by subscription, so compare the yearly total, especially once OBD trucks test four times a year from October 2027.
CTC Finder is an independent directory and is not affiliated with CARB. Rules change; check CARB's Clean Truck Check pages for the official version.