We come to your yard. CARB-credentialed HD I/M tester on-site. OBD & opacity testing — zero travel fees, zero hassle.
All prices include on-site compliance certificate. Free retest if a vehicle we test fails on retesting.
Stay compliant with CARB's Heavy-Duty Inspection and Maintenance (HD I/M) program. Here's what you need to know.
California's Heavy-Duty Inspection and Maintenance program requires periodic emissions testing for heavy-duty diesel vehicles operating in the state. Non-compliant vehicles face penalties and can be flagged at weigh stations or during roadside inspections.
Learn more at CARB →Clean Truck Check is the testing component of the HD I/M program. Credentialed testers like us perform OBD or opacity inspections and submit results directly to CARB. Passing vehicles receive a compliance certificate.
Clean Truck Check details →Vehicles must pass testing on a regular schedule — currently once per year, moving to twice per year in 2026. Non-compliance can result in fines of $1,000+ per vehicle, registration holds, and failed CHP inspections at weigh stations.
View CARB deadlines →2013+ model year: OBD (On-Board Diagnostics) test — checks ECM fault codes and emission readiness monitors. Pre-2013: OVI (Opacity/Visual Inspection) — SAE J1667 snap-acceleration smoke opacity test. Not sure? Call us and we'll determine the correct test for your fleet.
Call 209-818-1371 to find out →From the Port of Stockton to agricultural haulers, we know the Central Valley's compliance needs.
We cover the entire 209 area code — Stockton, Lodi, Manteca, Tracy, Modesto, Turlock, and everywhere in between. No extra fees to come to you.
5+ vehicles? You qualify for the Stockton Special — $40/truck. Select your vehicle count below and see your price instantly.
We'll call within 2 hours to confirm your appointment.
Questions? Call 209-818-1371 anytime.
The Stockton Special is an exclusive fleet discount: $40 per vehicle for OBD testing when you schedule 5 or more 2013+ model year trucks in a single appointment. It's only available in Stockton. Call 209-818-1371 to lock it in.
Under the Clean Truck Check program, most heavy-duty diesel trucks registered in California must pass regular emissions inspections. 2013+ model year trucks typically require OBD testing. Pre-2013 trucks may require an opacity (smoke) test. Our credentialed tester can confirm the requirement for your specific vehicles.
OBD tests take 15–25 minutes per vehicle. An opacity test takes 30–45 minutes per vehicle including warm-up and multiple snap-acceleration runs. For a fleet of 5 trucks, plan on 2–3 hours total.
We come to you — always. Our tester arrives with all equipment. You don't move a single truck. We can test at your yard, warehouse, job site, or any paved surface in the Stockton area. Zero travel fees.
If a vehicle we test does not pass and needs a follow-up inspection after repairs, we return to retest it at no additional charge. This applies to vehicles tested at our standard prices or Stockton Special pricing.
CARB can issue fines of $1,000 or more per non-compliant vehicle. Vehicles may also face registration holds and be flagged at CHP weigh stations. Starting in 2026, testing frequency increases to twice per year, making compliance even more critical. Learn more at CARB's Clean Truck Check page.
Refer a friend, fellow fleet owner, or anyone who books a test with us — you get $40 cash in hand when they complete their appointment. Get 10 referrals and earn $400. Just make sure they mention your name when booking.