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.
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.
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.
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
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
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.
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
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.
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).
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.
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.
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.
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.
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
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
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
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
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
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).
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
Either biennial (in conjunction with a DMV registration renewal
notice), change of ownership (selling a car), or initial (first
time registered in California).
The California license plate number on your vehicle. This field
is left blank when there is no license plate on the vehicle.
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
amount of each specific pollutant measured during the emissions
test of the vehicle.
vehicle manufacturer's model name.
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).
number of miles on your vehicle as reported by the technician based
on his or her reading of your vehicle's odometer.
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.
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
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.
/ 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 where the vehicle is registered.
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.
/ Number: The name of the licensed Smog Check technician
who performed the test, and his/her individual license number.
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
The actual weight of your vehicle as measured during the Smog Check.
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
Either manual (3-, 4-, 5-, or 6-speed) or automatic.
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
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.