Clean Truck Check guides

Plain-English answers about California's Clean Truck Check (HD I/M) program: who must test, when, what it costs and what happens if you miss a deadline.

What is Clean Truck Check?
Clean Truck Check is California's emissions testing program for diesel and alternative-fuel trucks over 14,000 lbs GVWR. Who must test, which test you need and how to comply.
Who needs Clean Truck Check, and who is exempt
Clean Truck Check covers nearly all diesel and alternative-fuel vehicles over 14,000 lbs GVWR on California roads, including out-of-state trucks. Full list of exemptions: zero-emission, emergency, military, historical and more.
Clean Truck Check deadlines for 2026 and 2027
When is my Clean Truck Check test due? Deadlines follow your DMV registration date, every six months, with a 90-day testing window. OBD trucks move to quarterly testing in October 2027.
Clean Truck Check in 2027: what changes for truck owners
Two Clean Truck Check changes in 2027: the annual fee rises to $33.12 per vehicle for deadlines from January 1, 2027, and OBD trucks move from two to four tests a year beginning October 2027.
Clean Truck Check for out-of-state trucks
Out-of-state and cross-border trucks that drive in California must still comply with Clean Truck Check, according to CARB. How to register, when to test and where to find testers outside California.
OBD test or smoke opacity test: which Clean Truck Check test your truck needs
Diesel trucks 2013 and newer and alternative-fuel trucks 2018 and newer get an OBD scan; diesel 2012 and older get a smoke opacity (SAE J1667) test plus visual inspection. What happens during each test and what to bring.
Remote, telematics and "test from your phone" Clean Truck Check: how it works
Can you do a Clean Truck Check without a shop visit? Yes for OBD trucks: a credentialed tester can use a CARB-certified telematics device or come to you. Certified devices, who submits the test, and what to ask before you pay.
How much does a Clean Truck Check cost?
Clean Truck Check test prices in California for 2026: published OBD test prices are mostly $50–$135 per truck, smoke opacity about $190–$200, plus CARB's $32.13 annual fee. Mobile and fleet pricing explained.
How to register your truck in CTC-VIS
Step-by-step guide to reporting a truck in CARB's CTC-VIS, paying the 2026 Clean Truck Check compliance fee ($32.13) and downloading your compliance certificate.
How to get your Clean Truck Check compliance certificate
Your Clean Truck Check compliance certificate is downloaded from CTC-VIS once the vehicle is reported, the annual fee has cleared and a passing test is on file. Timing, DMV updates and how to clear a Q212 hold.
Clean Truck Check fines and penalties
Missing a Clean Truck Check deadline can bring a DMV registration hold, citations and civil penalties of up to $10,000 per day per vehicle. How enforcement works and how to fix non-compliance.
How to become a CARB-credentialed Clean Truck Check tester
CARB's Clean Truck Check tester training and exam are free and online. Five steps to get credentialed, what equipment you need, how long the credential lasts and how to get listed.