Q. What is a "pre-inspection" and how do I get one?
A. Motorists who believe their vehicles may not pass initial smog certification at local Smog Check stations may request that an inspection be conducted before an official smog certification test. This procedure can help vehicle owners avoid their vehicles being designated as "Gross Polluters," requiring final inspection at a Test-Only Center or a Gold Shield station. Smog Check stations may charge for this service only if authorized by the consumer; BAR does not regulate those charges and receives none of the proceeds. The effectiveness of this program is subject to periodic review. Motorists should keep in mind that neither the pre-inspection (which is not an "official" inspection), nor any emissions repairs made subsequent to the preinspection, count toward the $450 repair cost waiver.
Q. What are the elements of a Smog Check?
A. In order for your vehicle to receive a Smog Check certificate, it must pass all the following elements of a Smog Check inspection:
- A visual inspection, in which required emissions control components and systems are identified, and must appear connected and functional.
- A functional inspection which includes, as applicable, checking the functionality and/or integrity of the emissions control malfunction indicator light ("Check Engine", etc), the ignition timing, the gas cap, and the Exhaust Gas Recirculation (EGR) system, if the vehicle is so equipped and a Two-Speed Idle (TSI) test is being performed. A Low Pressure Fuel
Evaporative Test (LPFET) is performed on all 1995 and older vehicles. A functional check of a vehicle's On-Board Diagnostic (OBD) system is also performed on 1996 and newer vehicles. Diagnostic information stored in the vehicle's computer is reported on the Vehicle Inspection Report (VIR) that the motorist receives at the end of the Smog Check inspection. OBD information can save time and money when repairs are required.
- A tailpipe emissions test, which measures exhaust emissions using a probe inserted into the vehicle's tailpipe during testing. Vehicles pass or fail this part of the Smog Check inspection based on established emission standards, sometimes called cutpoints.
Q. What is the "underhood" inspection portion of the Smog Check? Why is it necessary if you pass the tailpipe inspection?
A. The tailpipe test alone cannot guarantee that a car is not emitting harmful amounts of pollutants into California's air. In fact, to obtain a Smog Check certificate, a vehicle must pass all three portions of the Smog Check inspection-the visual, functional and tailpipe inspections (see previous question).
An "underhood" inspection comprises the visual and functional portions of the Smog Check inspection. The visual inspection ensures that the vehicle has all of the proper equipment and that none of its parts are disconnected or modified. The visual inspection helps prevent evaporative emissions. These occur even when the vehicle is parked, and may be the result of poorly connected or improper equipment.
On the old, two-speed idle (TSI) test, the functional inspection ensures that the ignition timing is set to the manufacturer's specifications and that the EGR valve is functioning. The functional portion of the TSI test is especially important because the tailpipe inspection cannot measure oxides of nitrogen (NOx) emissions-a key precursor to smog. The EGR test is not a part of the new dynamometer test, because that test does measure for NOx. The newest part of the functional test is the fuel cap test, which is used to help prevent evaporative emissions.
The visual and functional tests help identify vehicles with tampered emissions control systems. These vehicles may be configured to pass the tailpipe portion of the Smog Check inspection, but altered later to produce more emissions than allowed. This gave the previous program the reputation of passing vehicles which were "clean for a day," rather than clean until the vehicles' next Smog Check. Vehicles which were only "clean for a day" hindered California from meeting its clean air goals.
Q. What do I need to know about engine modifications?
A. WIn general, state and federal law prohibit modifications to your vehicle's emission control system. When repairing your vehicle, the emission-related parts used must be original equipment manufacturer (OEM) parts or be replacements for the OEM parts, as specified by the part manufacturer. Modifications to your emissions controls are not acceptable unless the parts used are approved/exempted by the California Air Resources Board.
The California Air Resources Board (CARB) grants exemptions in cases where the changes do not modify the performance of the emission controls in a way that causes an increase in emissions. CARB assigns the exempted parts an "executive order" (EO) number that may be used to verify acceptability. CARB provides a listing of
EO exempted parts on the CARB website.
Minor changes that do not affect the connectivity with or operation of other emission controls may be acceptable, for example,the installation of universal replacement hose in place of a preformed hose.
Q. Can I change the engine in my vehicle?
A. An engine change may not be performed if it degrades the effectiveness of a vehicle's emission control system. For more information, see BAR's
Engine Change Guidelines.
The following apply to any modifications or deviations from the original emission control configuration:
- You must use Original Equipment Manufacturers (OEM) specification parts for use in your specific year, make, and model of vehicle.
OR
- The part must have an Executive Order (EO) number that shows it has been exempted by the California Air Resources Board for use in your vehicle.
OR
- The equipment used must be certified by the U.S. Environmental Protection Agency (USEPA) for use in your specific year, make, and model of vehicle.
Check out the Bureau's
"Engine Change Guidelines" brochure on this Web site for additional information.
Q. What if I can't afford to repair my vehicle?
A. Please see the fact sheet:
Consumer Assistance Program
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