What the CARB OBD test checks on your truck
The CARB OBD test reads the emissions data your truck's on-board computer already keeps and records it for the Clean Truck Check program. It is the required test for 2013 and newer diesel engines and 2018 and newer alternative-fuel engines.
Our tester plugs CARB-verified equipment into the diagnostic port. Nobody drives the truck. In plain terms, the scan looks at:
- Whether the check engine light (MIL) is on
- Stored emissions-related fault codes
- Whether the readiness monitors have run and are set
Those same items cause most failures. The usual reasons a truck does not pass are a lit check engine light, readiness monitors that are not set (often after a battery disconnect or cleared codes), DPF and other emissions faults, and tampered or deleted equipment. Deleted systems fail and are illegal, and we do not help with them.
So the Clean Truck Check OBD pass requirements come down to a working emissions system with no open faults. If something is off, we explain the result in plain English so your shop knows what to fix before the retest. More detail: check engine light and readiness monitors.
OBD test for semi trucks of every brand
Every make takes the same heavy duty OBD test. Freightliner, Peterbilt, Kenworth, International, Volvo and Mack trucks with 2013 and newer diesel engines all use the CARB OBD test, whether the engine is a Cummins, Detroit, PACCAR, Volvo or Mack.
We test them all on site, including:
- Freightliner Cascadia and M2
- Peterbilt 579 and 389
- Kenworth T680 and T880
- International LT and ProStar
- Volvo VNL
- Mack Anthem and Granite
Day cab or sleeper, the process is the same: connect, read, record, explain. The brand matters far less than the condition of the emissions system. A Freightliner OBD test and a Peterbilt OBD test fail for the same reasons, such as an active check engine light or monitors that have not finished their drive cycle.
Medium-duty trucks follow the same rule. An OBD emissions test for a box truck works the same way when the vehicle is over 14,000 lb GVWR and falls under the program.
For brand-specific tips on readiness monitors and port locations, see OBD test by truck brand.
CNG, LNG, propane, hybrid and gasoline trucks
An alternative fuel truck emissions test in California depends on the engine year. CNG, LNG and other natural gas trucks with 2018 and newer engines take the same OBD test as a diesel. Alternative-fuel engines from 2017 and older that have no OBD get a visual inspection instead of an OBD scan.
Propane trucks, hybrid trucks and gasoline trucks over 14,000 lb GVWR can also fall under Clean Truck Check. These are the edge cases where details matter, so check CARB's rules for your vehicle before you book. If you are not sure what applies, call us. We help owners with CTC-VIS questions and can tell you which test the truck needs once we see the engine information.
Mixed fleets are common. A yard with natural gas tractors and older diesels can have OBD tests, smoke opacity tests and visual inspections done in one visit. See smoke opacity testing for the non-OBD side.
OBD test near me: we drive to the truck
You do not need to find an OBD test location. Diesel Dynamix brings the test to your yard, jobsite, terminal, port area or home anywhere in Southern California.
We cover Los Angeles, Long Beach, Orange County, the Inland Empire, San Diego and El Centro, plus the Ports of Los Angeles and Long Beach. Early-morning visits are available so trucks can test before they roll.
On OBD test cost: our price depends on how many trucks we test, the test type and the location. Fleets get per-truck pricing. We do not post a flat rate because one truck at a home driveway and twenty trucks at a terminal are different jobs.
For a quote, call or text (858) 342-8328, message us on WhatsApp, or book online. After the test you get the result, a plain-English explanation and the truck's next due date.
