--- title: Stay Compliant with Semi-Annual CARB Testing description: Stay compliant with CARB’s semi-annual testing—learn your deadlines and schedule fast, hassle-free mobile diesel testing with Sac Valley Mobile Diesel Test image: https://static.wixstatic.com/media/c17e34_4f3640b51a6b4ce186705ae802ff7461~mv2.png/v1/fill/w_1480,h_982,al_c,q_90,usm_0.66_1.00_0.01,enc_avif,quality_auto/c17e34_4f3640b51a6b4ce186705ae802ff7461~mv2.png --- [Skip to content](https://sacvalleydieseltesting.com/blog/stay-compliant-with-semi-annual-carb-testing#main-content) [![Screenshot 2025-02-18 at 10.34.07 PM](https://sacvalleydieseltesting.com/hs-fs/hubfs/Screenshot%202025-02-18%20at%2010.34.07%20PM.png?width=244&height=121&name=Screenshot%202025-02-18%20at%2010.34.07%20PM.png)](https://sacvalleydieseltesting.com) - [Home](https://sacvalleydieseltesting.com) - [About](https://sacvalleydieseltesting.com/carb-info) - [Blog](https://sacvalleydieseltesting.com/blog) - [FAQ](https://ww2.arb.ca.gov/our-work/programs/inspection-and-maintenance-program/hd-im-fact-sheets) - [Diesel Motorhomes](https://sacvalleydieseltesting.com/motorhome-carb-testing) Open main navigation Close main navigation - [Home](https://sacvalleydieseltesting.com) - [About](https://sacvalleydieseltesting.com/carb-info) - [Blog](https://sacvalleydieseltesting.com/blog) - [FAQ](https://ww2.arb.ca.gov/our-work/programs/inspection-and-maintenance-program/hd-im-fact-sheets) - [Diesel Motorhomes](https://sacvalleydieseltesting.com/motorhome-carb-testing) - [530-650-6646](tel:5306506646) [530-650-6646](tel:5306506646) [All posts](https://sacvalleydieseltesting.com/blog/all) February 17, 2025 # Stay Compliant with Semi-Annual CARB Testing By  Nathan Ament  ·  1 minute read If you're a trucker, fleet manager, or RV owner in California, you know how important it is to stay compliant with CARB's Clean Truck Check program. The semi-annual Heavy-Duty Inspection and Maintenance (HD I/M) testing is now required, and missing your deadline could mean hefty fines. At Sac Valley Mobile Diesel Testing we make it quick and easy to get your compliance testing done—on your schedule! ...   **When Is Your CARB Test Due?** Your testing deadlines are based on your vehicle's registration month. You need to complete a CARB compliance test twice a year—once in your registration month and again six months later.   Here's a simple way to remember:   If your registration month is April (as shown in the picture of license plate below), your tests are due by April 30th and October 31st. If your registration month is September, your tests are due by March 31st and September 30th.   ![Screenshot 2025-02-16 at 4.55.43 PM](https://sacvalleydieseltesting.com/hs-fs/hubfs/Screenshot%202025-02-16%20at%204.55.43%20PM.png?width=2104&height=630&name=Screenshot%202025-02-16%20at%204.55.43%20PM.png)         ![](https://static.wixstatic.com/media/c17e34_014f963a5a514ce78f0f6176aa8eb2da~mv2.jpeg/v1/fill/w_722,h_362,al_c,lg_1,q_80,enc_avif,quality_auto/c17e34_014f963a5a514ce78f0f6176aa8eb2da~mv2.jpeg)     ![](https://static.wixstatic.com/media/c17e34_4f3640b51a6b4ce186705ae802ff7461~mv2.png/v1/fill/w_1480,h_982,al_c,q_90,usm_0.66_1.00_0.01,enc_avif,quality_auto/c17e34_4f3640b51a6b4ce186705ae802ff7461~mv2.png)     Don't wait until the last minute! There's a 90-day testing window before each deadline, so you can test early. This gives you extra time to make any necessary repairs if your vehicle happens to fails the OBD or Smoke Opacity Test. BTW, you will need only one test, it's either the OBD or the Smoke Opacity test. It's never both. It just depends on the year of your engine. Also make sure your engine label is clearly legible. Some people paint over it, or it's missing. You cannot pass the Smoke Opacity/OVI test without a legible label.   Why Test Early? Testing early helps you avoid penalties for missing deadlines, reduces downtime if repairs are needed, keeps your fleet running without last-minute stress, and ensures priority service with Sac Valley Mobile Diesel Testing.     Fast, Reliable, and Mobile Testing At Sac Valley Mobile Diesel Testing, we bring the test to you! Why leave it at the shop and get it back who knows when?     Whether you're in Sacramento, the Bay Area, or just about anywhere in Northern California, we provide onsite testing for trucks, fleets, and motorhomes. No waiting in long lines, no hassle—just fast, professional service to keep you compliant. We offer easy scheduling, same-day & next-day appointments if available, and fleet discounts for multiple vehicles.     Book Your CARB Test Today! Don't risk fines or downtime. Get your semi-annual CARB test done the easy way with Sac Valley Mobile Diesel Testing.       **Call Now: 530-650-6646**   **Visit: [www.sacvalleydieseltesting.com](https://sacvalleydieseltesting.com/)**     Share [facebook-f icon](http://www.facebook.com/share.php?u=https://sacvalleydieseltesting.com/blog/stay-compliant-with-semi-annual-carb-testing) [linkedin-in icon](http://www.linkedin.com/shareArticle?mini=true&url=https://sacvalleydieseltesting.com/blog/stay-compliant-with-semi-annual-carb-testing) [twitter icon](https://twitter.com/intent/tweet?url=https://sacvalleydieseltesting.com/blog/stay-compliant-with-semi-annual-carb-testing) [pinterest-p icon](http://pinterest.com/pin/create/link/?url=https://sacvalleydieseltesting.com/blog/stay-compliant-with-semi-annual-carb-testing) [envelope icon](mailto:?body=https://sacvalleydieseltesting.com/blog/stay-compliant-with-semi-annual-carb-testing) [![](https://sacvalleydieseltesting.com/hs-fs/hubfs/Screenshot%202024-09-02%20at%209.04.58%20AM-1.png?width=444&height=228&name=Screenshot%202024-09-02%20at%209.04.58%20AM-1.png)](https://sacvalleydieseltesting.com/)   Learn more about the California Air Resources Board HD/IM Diesel Emissions Program that goes into effect this year by clicking on the links under Resources.       [facebook-f icon](https://www.facebook.com/profile.php?id=61570893532975) [linkedin-in icon](https://www.linkedin.com/company/106506390/admin/dashboard/) [youtube icon](https://youtu.be/mwR0TwFdHPU?si=uVxVAgoWq2lVix7B) instagram icon ## **Resources** [Clean Truck Check Website](https://ww2.arb.ca.gov/our-work/programs/CTC) [Truck Stop Videos - Including Spanish Versions](https://www.youtube.com/@carbtruckstop5804/videos) [CARB Motorhome FACT SHEET](https://ww2.arb.ca.gov/resources/fact-sheets/clean-truck-check-motorhome-fact-sheet) [The NEW Semi-Annual Testing Requirements](https://ww2.arb.ca.gov/clean-truck-check-requirements-vehicles-subject-semi-annual-compliance) [CARB info VIDEO](https://ww2.arb.ca.gov/our-work/programs/truckstop-resources/truckstop/training-course-clean-truck-check-hd-im-program) [Testing Twice A Year - Calendar](https://ww2.arb.ca.gov/clean-truck-check-requirements-vehicles-subject-semi-annual-compliance) [Vehicle Inspection System (CTC-VIS) Portal](https://cleantruckcheck.arb.ca.gov) [Database Reporting Instructions CTC-VIS](https://youtu.be/Zd1YaEBM-hE?si=KXFPV6TxuKQ6yM21) [DPF Maintenance](https://youtu.be/NB_dZTnhYTs?si=gC8S-TU8bzEdbekw) [Information About Selling a Vehicle](https://ww2.arb.ca.gov/resources/fact-sheets/dealer-fact-sheet-clean-truck-check) [Information About Clearning Codes](https://ww2.arb.ca.gov/board-diagnostic-obd-readiness-criteria) [Acceptable Smoke Levels For Smoke Tests](https://ww2.arb.ca.gov/sites/default/files/inline-images/Opacity%20%25s.png) [Missing Engine Label Information](https://ww2.arb.ca.gov/resources/fact-sheets/clean-truck-check-what-do-when-ecl-missingillegible) [Our Site Data Privacy Policy\*](https://www.freeprivacypolicy.com/live/4839b8f5-5648-436e-9a7c-d6f08e41b09e)   ![CTC_Testers_hrz-white](https://sacvalleydieseltesting.com/hubfs/CTC_Testers_hrz-white.svg "CTC_Testers_hrz-white") Information about CARB and HD/IM Program is subject to change, for the most accurate and up-to-date information go to the California Air Resouces Board Website                                                                                                                                                                                                                    Copyright © 2026, Sac Valley Mobile Diesel Testing ```json { "@context" : "https://schema.org", "@type" : "BlogPosting", "author" : { "@type" : "Person", "name" : "Nathan Ament", "url" : "https://sacvalleydieseltesting.com/blog/author/nathan-ament" }, "dateModified" : "2025-02-17T02:00:20.253Z", "datePublished" : "2025-02-17T01:58:27.000Z", "headline" : "Stay Compliant with Semi-Annual CARB Testing", "image" : [ "https://static.wixstatic.com/media/c17e34_4f3640b51a6b4ce186705ae802ff7461~mv2.png/v1/fill/w_1480,h_982,al_c,q_90,usm_0.66_1.00_0.01,enc_avif,quality_auto/c17e34_4f3640b51a6b4ce186705ae802ff7461~mv2.png" ], "mainEntityOfPage" : { "@id" : "https://sacvalleydieseltesting.com/blog/stay-compliant-with-semi-annual-carb-testing", "@type" : "WebPage" }, "publisher" : { "@type" : "Organization", "logo" : { "@type" : "ImageObject", "url" : "https://sacvalleydieseltesting.com/hubfs/Screenshot%202024-09-02%20at%209.04.58%20AM-1.png" } } } ``` ```json { "@context" : "http://schema.org", "@type" : "Article", "author" : { "@type" : "Person", "name" : [ "Nathan Ament" ] }, "datePublished" : "2025-02-17T01:58:27+0000", "description" : "Stay compliant with CARB’s semi-annual testing—learn your deadlines and schedule fast, hassle-free mobile diesel testing with Sac Valley Mobile Diesel Test", "headline" : "Stay Compliant with Semi-Annual CARB Testing", "image" : "https://static.wixstatic.com/media/c17e34_4f3640b51a6b4ce186705ae802ff7461~mv2.png/v1/fill/w_1480,h_982,al_c,q_90,usm_0.66_1.00_0.01,enc_avif,quality_auto/c17e34_4f3640b51a6b4ce186705ae802ff7461~mv2.png", "publisher" : { "@type" : "Organization", "logo" : { "@type" : "ImageObject", "url" : "https://46144935.fs1.hubspotusercontent-na1.net/hubfs/46144935/Screenshot%202024-09-02%20at%209.04.58%20AM-1.png" }, "name" : "Sac Valley Mobile Diesel Testing" }, "url" : "https://sacvalleydieseltesting.com/blog/stay-compliant-with-semi-annual-carb-testing" } ```