Inspection Tips for Gasoline-powered Vehicles


What is involved in an emission inspection?

There are three main components of an emission inspection:

  1. A fuel cap inspection to ensure an adequate seal to prevent exhaustive emissions from the tank
  2. A visual inspection of the catalytic converter
  3. Evaluation of the emissions control system

For vehicles 1996 and newer, emissions testing uses computerized equipment to capture information from your vehicle's On-Board Diagnostic (OBD) system to determine if your emissions system is operating properly. 

For vehicles 1995 and older, our inspector will drive your vehicle onto a "dynamometer" to simulate driving conditions (like a treadmill for your vehicle) while a tailpipe analyzer measures emissions. If excessive amounts of hydrocarbons, carbon monoxide or oxides of nitrogen are detected, your vehicle may fail its emissions test.

If your report shows excessive hydrocarbon (HC) emissions, it is an indication that the fuel in your engine is not burning completely. This can be caused by a problem with the engine, air pump, ignition system, exhaust gas recirculation system (EGR), catalytic converter, or gas cap.

If excessive carbon monoxide (CO) is detected, there may be either too much or too little air reaching the combustion chamber. This could be cased by a misadjusted carburetor, worn out rings or valve guides, or problem with the fuel injection or air pump systems.

If high oxides of nitrogen (NOx) are found, it can mean that you have a faulty catalytic converteror there may be too high temperatures in the combustion chamber caused by deposits or problems with related components. Check the air injection system, exhaust gas recirculation system (EGR), oxygen sensor, catalytic converter, and combustion chamber.

If your vehicle passes its inspection, the Georgia Department of Motor Vehicles (DMV) will receive an electronic confirmation of your successful inspection to allow you to complete your vehicle registration online or in a tag office.

If your vehicle fails its inspection, you'll receive information about the cause of failure for you to address yourself or with your mechanic. Once the problem is resolved, stop back at the inspection station within 30 days for a free retest.


Which vehicles require an emissions inspection?

The rules for emission inspections vary by the county of the vehicle's registration and the type and model year of your vehicle.

1) Only certain counties require an emissions inspection. 
There are 13 counties in the metro Atlanta area that require an emissions inspection:

  • Cherokee County
  • Clayton County
  • Cobb County
  • Coweta County
  • DeKalb County
  • Douglas County
  • Fayette County
  • Forsyth County
  • Fulton County
  • Gwinnett County
  • Henry County
  • Paulding County
  • Rockdale County

If your vehicle is registered in a county not mentioned above, an emissions test is not required prior to your vehicle's registration renewal.

2) Very old and very new vehicles are exempt from emissions testing.

  • Vehicles less than 2 model years old do not need an emissions test.
  • Vehicles 25 model years or older do not need an emissions test.

3) Certain types of vehicles do not require an emissions inspection.
Most vehicles that can run on gasoline and have a gross vehicle weight rating of 8,500 pounds or less require an emissions test. This includes passenger cars, SUVs, pick-up trucks, and most light-duty trucks.

If you have a hybrid or flex-fuel vehicle, check our Tips for Alternative-fueled Vehicles for more information.

Currently the following vehicle types are exempt from emissions testing in Georgia:

  • Diesel-powered vehicles
  • Fully electric vehicles
  • Motorcycles
  • Recreational vehicles (RVs) and motor homes


Tips for passing your inspection:

The following tips will help your car pass its inspection, and at the same time help the environment!

  • Regular maintenance
    Change your oil and filters as recommended by your vehicle's manufacturer (usually every 3 months or 3,000 miles) to help your vehicle operate efficiently and increase its odds of passing the emission test. It is also important to use the type of oil and fuel recommended by the manufacturer for best performance.
  • Watch for leaks
    Low fluid levels can affect the efficiency and performance of your vehicle, which can cause a test failure.
  • Gas cap required
    State regulations require that your gas cap is in place and is of the correct type for your vehicle to avoid excess evaporative emissions. This is important, as not only can a properly fitting cap save you money at the pump, but too much evaporative emissions can trigger your vehicle's check engine light and produce a test failure.
  • Watch for warning lights
    For vehicles model year 1996 and newer, the same "On Board Diagnostics" system in your vehicle that triggers the warning light is the same system that reports its information to our inspection station's computer determining if your vehicle meets state requirements, so if your vehicle's computer is triggering a "Check Engine" light, it may not pass the inspection.
  • New or disconnected battery?
    If your battery is disconnected, or if it died and needed a jump start, your vehicle's computer system resets itself and would fail due to a lack of data even if your vehicle is operating properly. Driving between 100 - 150 miles (consult your vehicle's manual for an exact number) before coming in for your inspection will make sure your vehicle has gathered enough information for its test
  • Take notice of warning signs
    Road-weary vehicles can start to show signs of a faulty emissions system, including difficulty starting or staying running at idle, jumping or shaking at higher speeds, and misfires. Taking your vehicle to a certified repair shop as soon as you notice a worsening trend can catch problems before they escalate into a more major repair or test failure.


Extra tips for vehicles model year 1995 and older:

As older vehicles do not have the advanced computer systems installed to gather information about your car's emissions, we use equipment to take measurements. Follow these tips for a smoother inspection (and safer driving!)

  • Warm it up
    Drive your vehicle for at least 15 minutes prior to your emission test, as it produces extra pollutants until it reaches normal operating temperature. Vehicles not driven often may experience carbon build-up which can cause an emission test failure, so warm them up a little longer (30 minutes is plenty) at highway speeds.
  • Properly inflate your tires
    Under-inflated, mismatched, or unevenly inflated tires make the vehicle difficult to test on the dynamometer. Not only is this important for your inspection, but is safer for everyday driving and helps your vehicle operate more efficiently.
  • Stopping power
    Poor brakes make the vehicle difficult to test on the dynamometer.
  • All-wheel drive or Traction control?
    Let us know before starting the test if your vehicle has all-wheel drive and/or traction control features.


Visit a DEKRA station for more expert advice and a fast, professional vehicle inspection.


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