Smog Check Program’s Updated Test Technology

Californians getting Smog Checks today may notice that the traditional tailpipe test used for many years has been replaced by a quicker, computer-based test for gasoline-powered cars model-year 2000 and newer, and for most diesel vehicles that are model-year 1998 and newer.

This updated test uses the diagnostic capabilities of the vehicle’s computer system instead of the traditional tailpipe probe to measure the vehicle’s emissions. This On-Board Diagnostic (OBD) system gathers information and determines if the vehicle’s emission control systems are operating properly. A visual inspection of emission control components is still required as well.

The OBD only method of testing vehicles is the result of 2010 legislation (AB 2289-Eng) which is designed to improve the Smog Check Program and further reduce air pollution. The Smog Check program removes hundreds of tons of smog-forming pollutants from California’s air every day.

Gasoline-powered vehicles model-year 1999 and older will continue to receive Smog Checks using a tailpipe probe as well as the OBD test.

Hybrid Vehicles

Hybrid vehicles have always been subject to Smog Check inspections. However, since their introduction to the California market in 2000, hybrid vehicles could not be properly tested using the traditional tailpipe test. During a traditional Smog Check, emissions are measured at low speeds or idle rates. At these lower speeds, however, hybrids switch to their electric motors, making it impossible to measure the emissions of their gasoline engines. The OBD only test now makes it possible to test these vehicles. It is important to remember that hybrids have internal combustion engines which generate pollution.

Registration renewal notices for hybrid vehicles needing a Smog Check will begin going out in the mail starting in April 2015 (for registrations due in July 2015). As with other vehicles, owners selling their hybrid vehicles are required to have a change of ownership Smog Check inspection done before they can sell their vehicles. Smog Checks are also now required for all out-of-state hybrid vehicles registering in California for the first time.

Smog Check Requirements

A Smog Check is required every other year for registration renewal of:

  • 1976 and newer model-year gas-powered, hybrid, and flex-fuel vehicles
  • 1998 and newer model-year diesel-powered vehicles with a gross vehicle weight rating of 14,000 pounds and less


  • Vehicles that are six model-years old and newer are not subject to the every-other-year Smog Check requirement since newer vehicles are considered cleaner, and less likely to fail a Smog Check.
  • Vehicles four model-years old and newer do not require a Smog Check upon change of ownership.
  • Note: These exceptions are not applicable to diesel-powered vehicles.

About Smog Check

The Smog Check Program is administered by the California Department of Consumer Affairs’ Bureau of Automotive Repair and is an important part of the State’s efforts to improve the quality of the air we breathe. The Smog Check Program removes hundreds of tons of smog-forming pollutants from California’s air every day. Smog Check inspections are designed to identify vehicles with excess emissions so they can be properly repaired to meet state and federal emissions standards.



Robertson Gomez Automotive


503 North H Street. Lompoc, CA. 93436


(805) 736-9332


Mon. - Thur. 8 A.M. - 4:30 P.M

Friday  8 A.M. - 4:00 P.M.

Sat. 8:30 A.M. - 11:30 A.M. (SMOG ONLY)

Automotive Service Excellence Certified. Certificates: A1- A8 • T-1 • L-1

Licensed by the State of California. Smog Check • Inspection • Repair Station

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