%CO2: Carbon Dioxide is a colorless, odorless gas which is a byproduct of most combustion processes and also of human respiration. It is the same gas found in soda pop. High levels of CO2 in exhaust typically indicate greater engine efficiency; however, CO2 is considered a greenhouse gas that may cause global warming. High or low levels of carbon dioxide emissions are not grounds for a vehicle failing the Smog Check; the measurement is meant as a diagnostic tool for technicians. CO2 is measured in percent.

%O2: Oxygen is a colorless, odorless gas necessary for life on the planet and also for engine combustion to occur. The atmosphere is comprised of approximately 21% oxygen. High levels of O2 emissions can indicate a problem with the catalytic converter. High or low levels of O2 emissions are not grounds for a vehicle failing the Smog Check; the measurement is meant as a diagnostic tool for technicians. O2 is measured in percent.

Air Injection: Also known as the smog pump. Pumps air into the exhaust manifold to burn unburned fuels (hydrocarbons).

AVE: The average emissions for vehicles in the same Emissions Standards Category (ESC). ESCs are based on model year and whether the vehicle is a passenger car or a light-, medium-, or heavy-duty truck. The average emissions reading is meant as a guidepost for technicians when repairing vehicles that fail a Smog Check; it has no effect on the pass/fail result of the emissions test.

Acceleration Simulation Mode (ASM): This is the test type for vehicles operated on a dynamometer (treadmill like device) which simulates actual driving conditions.

Bureau of Automotive Repair (BAR): Part of the California Department of Consumer Affairs, the Bureau of Automotive Repair (BAR) is a consumer protection agency focused exclusively on automotive repair issues. BAR licenses auto repair dealers, Smog Check stations, and Smog Check technicians. BAR administers the Smog Check program, as required by law. BAR investigates complaints from consumers about auto repair establishments, and recovers millions of dollars for consumers each year. BAR is completely separate from the Department of Motor Vehicles and the Air Resources Board.

Catalytic Converter: Located between the exhaust manifold and the muffler, this device uses precious metals as a catalyst to turn hydrocarbons, carbon monoxide, oxygen, and oxides of nitrogen into carbon dioxide and water vapor.

Certification: Indicates whether your vehicle was manufactured to meet United States Environmental Protection Agency or more stringent California emissions standards.

Carbon Monoxide (CO (%): Carbon Monoxide is a colorless, odorless gas that is fatal to many life forms in moderate concentrations. CO emissions are often the byproduct of an overly rich fuel mixture. Unhealthy levels of CO emissions result in a vehicle failing its Smog Check. CO is measured in percent.

Consumer Assistance Program (CAP): The Consumer Assistance Program is available at participating Gold Shield stations for motorists who need financial assistance (up to $500) making repairs to their vehicle when it fails a biennial (every other year) Smog Check. Click here to learn more about the Consumer Assistance Program and to obtain an application, or visit our Web site at www.smogcheck.ca.gov.

Cylinders: The number of combustion cylinders in the engine (usually 4, 6, or 8).

DMV ID Number: A number used to locate the electronic smog certificate in the event it is electronically misfiled.

EGR Functional: During the Smog Check inspection, the technician performs a functional test of the EGR system per the vehicle manufacturer's instructions. This ensures the EGR system is operating as designed.

EGR Visual: As part of the Smog Check inspection, the technician performs a visual inspection of all emission components the vehicle is equipped with, including the EGR system. The technician visually inspects the EGR valve and associated plumbing for defects or modifications. The technician will either pass or fail the fuel cap visual test based on observations made during the test.

Emissions Control System (ECS): The Emissions Control System is any of a number of separate emissions control components which, together, reduce the level of pollutants emitted from a vehicle.

Exhaust Gas Recirculation (EGR) System: The vehicle's Exhaust Gas Recirculation system reroutes exhaust gases back through the intake manifold to lower engine temperatures and, in so doing, reduces NOx emissions. The EGR functional test is part of the two-speed idle (TSI) test, but is not necessary for the ASM (BAR-97) test because that equipment tests for NOx.

Emissions Inspection System (EIS): The EIS can be defined as the complete BAR97 system, the analyzer, dynamometer and peripheral devices.

Emission Standards Category (ESC): ESCs are the pass/ fail emission level cut points for a specific class of vehicles. For example, 1975 through 1978 trucks with a Gross Vehicle Weight Rating (GVWR) over 8500 pounds would have the same cut points, therefore, they are in the same ESC.

Emissions Test: The third of the three vital parts of the California Smog Check. This is where the emissions analyzer tests actual emissions from your vehicle, as measured at the tailpipe. Only the emissions test can label a car a Gross Polluter. Emissions measured include Carbon Monoxide (CO), Carbon Dioxide (CO2), Hydrocarbons (HC) and Oxygen (O2). In California's most polluted urban areas (Enhanced Areas), the emissions test also measures levels of oxides of nitrogen (NOx).

Engine Size: Measured in displacement of either cubic inches, cubic centimeters, or cubic liters.

Evaporative Emission Control System (EVAP): The EVAP system prevents raw gasoline from escaping the vehicle and evaporating into the atmosphere. As part of the inspection, the technician visually inspects the EVAP system and associated plumbing for defects or modifications. The technician will either pass or fail the EVAP system based observations made during the test.

Exhaust: Usually either single (one pipe) or dual (two pipes).

Exhaust Gas Recirculation (EGR): The vehicle's Exhaust Gas Recirculation system reroutes exhaust gases back through the intake manifold to lower engine temperatures and, in so doing, reduces NOx emissions. The EGR functional test is part of the two-speed idle (TSI) test, but is not necessary for the ASM (BAR-97) test, because that equipment tests for NOx.

Fail: The level of harmful emissions from this vehicle, on this portion of the test, exceeds the range of what is reasonable for this model/engine combination, and is contributing to unhealthy air in California.

Fillpipe Restrictor: A functional test of the fuel pipe restrictor is performed only on vehicles being initially registered in California. If the fuel pipe restrictor is oversized due to tampering, then the fuel pipe restrictor functional test fails.

Fuel EVAP Functional: A functional test of the evaporative emission control system is under development by the Bureau. Until the test is implemented, the technician will enter "non applicable" into the analyzer for this test.

Fuel Cap Integrity Test: Tests whether gasoline fumes can leak out from your tank around the cap. Gasoline fumes contain high levels of harmful pollutants, including benzene, a known carcinogen. Studies by the United States Environmental Protection Agency show that around 30 percent of all the emissions from a vehicle are in the form of fuel evaporation, usually from the fuel tank.

Fuel Cap Visual Test: As part of a Smog Check inspection, the technician visually inspects the fuel tank cap for defects, (i.e. cracked or deteriorated rubber seal). The technician will either pass or fail the fuel cap visual test based on observations made during the test.

Fuel Evaporative Controls: Also known as the charcoal canister, this system stops vapors from the carburetor bowl and the gas tank from evaporating into the atmosphere.

Fuel Type: Only vehicles fueled by gasoline, natural gas, and propane are currently included in the Smog Check program. Light-duty diesel vehicles are excluded.

Functional Inspection: The second of the three vital parts of the California Smog Check. The functional check ensures the correct vehicle timing and EGR System function. The engine malfunction light is also part of the functional inspection. Emissions system defects identified during the functional inspection are considered unhealthy for the air and result in an overall Smog Check failure.

Gold Shield Dealer: The Gold Shield Dealer station sub-type is a new car dealer in a Basic or Change of Ownership area and has the ability to smog enhanced area cars that are to be sold in their program area.

Gold Shield Station: The Gold Shield Station type has meet certain performance criteria and performs CAP repairs.

GP: The emissions level, or "cut point," at which a vehicle fails as a Gross Polluter. The emissions of a gross polluter are typically at least twice as high as those of an ordinary failing vehicle. Repairs on a Gross Polluter must be verified at a Test-Only or Gold Shield station. (Click here for Test-Only or Gold Shield station listings).

Gross Polluter: The emissions levels, or "cut points," established for the highest-polluting vehicles. The emissions of a Gross Polluter are typically at least twice as high as those of an ordinary failing vehicle. Repairs on a Gross Polluter must be verified at a Test-Only or Gold Shield station. (Click here for Test-Only or Gold Shield station listings).

Gross Vehicle Weight Rating (GVWR): Gross Vehicle Weight Rating is the weight of the vehicle plus the maximum load it is designed to carry. This differs from the vehicle's Test Weight.

Hydrocarbons (HC) (PPM): Hydrocarbons are the component of fuels that produce energy. HC emissions from a vehicle are basically unburned fuel. High levels of HC emissions indicate incomplete fuel combustion, either the result of a misfire or of low engine compression. Unhealthy levels of HC emissions result in a vehicle failing its Smog Check. Hydrocarbons are measured in parts per million (PPM).

Ignition Timing: The timing of the spark relative to the operation of the valves and the placement of the piston in the cylinder. BTDC stands for "before top dead center" a reference to a mark on the main pulley on the front of the engine. For most engines, when the timing is set to 0 degrees TDC, the number one piston will fire at the very top of the stroke. For vehicles where the manufacturer specifies a timing setting, the Smog Check inspection allows plus or minus three degrees from that setting. For vehicles where the manufacturer specifies a timing range, the vehicle must be within that timing range. Advanced timing is when the spark fires before the piston has reached the top of the stroke. Retarded timing is when the spark fires after the piston has reached the top

Inspection Reason: Either biennial (in conjunction with a DMV registration renewal notice), change of ownership (selling a car), or initial (first time registered in California).

License: The California license plate number on your vehicle. This field is left blank when there is no license plate on the vehicle.

Make: The vehicle manufacturer's brand name.

MAX: The maximum allowable emissions for the particular make, model, and year of vehicle. Vehicles with emissions that exceed this level, or "cut point," fail the emissions portion of the Smog Check. There are separate cut points for vehicles failing at ordinary vs. Gross Polluter levels.

MEAS: The amount of each specific pollutant measured during the emissions test of the vehicle.

Model: The vehicle manufacturer's model name.

Model-Year: The vehicle manufacturer's model year for your vehicle. Not necessarily the year the vehicle was built.

NO (PPM): Oxides of nitrogen (more commonly called NOx) are odorless gases that help form smog, and give smog its characteristic brown color. NO is produced when temperatures in the combustion chambers exceed 2500 degrees Fahrenheit. Excessive engine temperatures could be caused by a lean fuel mixture, by retarded timing, by carbon buildup inside the combustion chamber, or by a malfunctioning engine cooling system. The function of the EGR System is to reduce NO. Unhealthy levels of NO emissions result in a vehicle failing its Smog Check. NO is measured in parts per million (PPM).

Odometer: The number of miles on your vehicle as reported by the technician based on his or her reading of your vehicle's odometer.

Oxygen Sensor: A device located in the exhaust manifold or exhaust pipe which compares the level of oxygen in the ambient air to the level of oxygen in the exhaust stream and sends a signal to the vehicle's onboard computer, which adjusts the fuel mix accordingly.

Parts Per Million (PPM): This is a unit of measurement for both Oxides of Nitrogen and Hydrocarbons which are measured by the BAR97 emissions analyzer.

Pass: The level of harmful emissions from this vehicle, on this portion of the test, is within the range of what is reasonable for this model/engine combination. Thank you for doing your part to improve our air quality to healthy levels in California.

Positive Crankcase Ventilation (PCV): Positive Crankcase Ventilation removes gases blown around the pistons and rings from the engine crankcase, and reroutes them through the intake manifold to be burnt again.

Regular Test and Repair: The Regular Test and Repair Station type performs inspections and repairs all types of vehicles. This station type does not have the ability to certify directed (Test Only) vehicles or vehicles with emissions in the gross polluter range.

Revolutions Per Minute (RPM): Revolutions per minute is a measurement of engine speed. Engine turning speed typically does not correspond to the speed of the vehicle.

Repair Tech Name / Number: The name of the licensed Smog Check technician who repaired the vehicle, if applicable or known.

Smog Check Certificate Number: This is the number of the electronic certificate sent to the Department of Motor Vehicles (DMV) which allows the owner to complete his or her registration. The Vehicle Inspection Report is proof of the vehicle passing a Smog Check.

Software Version / EIS Number: The BAR-certified version of the software that the emissions analyzer unit used during the test, and the unique identification number for the analyzer unit.

State: The state where the vehicle is registered.

Station Number: The license number of the Smog Check station where the test was performed.

System Malfunction Light: Also known as the "check engine light," this early warning signal in the vehicle cabin indicates engine problems. Such problems could cause serious performance or engine problems for the vehicle if not checked and repaired, and could lead to excessive amounts of pollution being emitted during certain driving conditions which may not be detected during a Smog Check.

Technician Name / Number: The name of the licensed Smog Check technician who performed the test, and his/her individual license number.

Test: The Acceleration Simulation Mode (BAR-97) test measures vehicle emissions levels at 15 mph and 25 mph with driving conditions simulated by the dynamometer, a treadmill-like device. The two-speed idle (TSI or BAR-90) test measures the emissions levels of a stationary vehicle at two engine idle speeds.

Test Only: The Test Only station type has the ability to test and certify all vehicles, though it cannot perform any repairs.

Test Weight: The actual weight of your vehicle as measured during the Smog Check.

Thermostatic Air Cleaner: Draws warm air into a cold engine to help fuel vaporize before burning. This system is important before the engine warms up, to improve cold drivability and cold-engine emissions reductions.

Transmission: Either manual (3-, 4-, 5-, or 6-speed) or automatic.

Type: Vehicles eligible for the Smog Check program include passenger cars, light-duty trucks and heavy-duty trucks.

Vacuum Lines to Sensors/Switches: A visual inspection of the vacuum lines to the sensors and switches in all of the emission control systems on the vehicle is performed. The technician will either pass or fail the these components based on observations made during the test.

Vehicle Identification Number (VIN): Your vehicle's unique identification number, usually 17 digits but sometimes less. Typically found on the top of the dash just inside the windshield on the driver's side, or on a plate/sticker in the driver's side door jamb. The BAR code on your DMV registration renewal also contains this number. Contact the DMV if the VIN on your vehicle does not match the VIN on your registration form.

Visual Inspection: The first of the three vital parts of the California Smog Check. The visual inspection checks for missing, disconnected, or visibly damaged emissions-system components, including the catalytic converter, the thermostatic air cleaner, the heat riser and the smog pump. Emissions system defects identified during the visual inspection are considered unhealthy for the air and result in an overall Smog Check failure.

VLT Record #: Your vehicle's record on the Bureau of Automotive Repair's Vehicle Lookup Table (VLT). The table contains specific information for each vehicle model and engine combination available. Information from the VLT regarding your vehicle's weight and aerodynamic resistance allows the Smog Check emissions analyzer to correctly set the resistance on the dynamometer (a treadmill-like device used to test vehicles in the smoggiest urban areas of the state).

Wiring to Sensors/Switches: A visual inspection of the wiring to the sensors and switches in all of the emission control systems on the vehicle is performed. The technician will either pass or fail the these components based on observations made during the test.

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