Inspection Tips for Alternative-fueled Vehicles

Which alternative-fueled vehicles require an emissions inspection?

If your passenger vehicle is capable of operating on gasoline, and you live in the metro Atlanta area (check our Tips for Gasoline-powered Vehicles for a list of counties), then you will need to have your vehicle tested prior to renewing your registration.

According to the State of Georgia's program rules, it doesn't matter if you prefer to operate your bi-fueled or flex-fuel vehicle with an alternate fuel. If the manufacturer's design allows it to operate on gasoline, then it must be tested. In fact, state regulations require you to fill your tank with 100% gasoline prior to the emissions test.

Examples of vehicles that must undergo emissions testing include:

  • Toyota Prius
  • Toyota Highlander Hybrid
  • Ford Escape Hybrid
  • Honda Insight
  • Honda Civic Hybrid
  • Honda Accord Hybrid
  • Lexus RX Hybrid
  • Mercury Mariner Hybrid


Which alternative-fueled vehicles do not require an emissions inspection?

If your vehicle is dedicated to only operate on an alternate fuel according to manufacturer design, then an emissions inspection is not required. This includes:

  • Vehicles operating on only Battery Electricity
  • Vehicles operating on only Natural Gas
  • Vehicles operating on only Propane
  • Vehicles operating on only Hydrogen


What is involved in an emissions inspection on an alternative fueled vehicle?

There are three main components of an emission inspection for an alternative fueled vehicle:

  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 using computerized equipment to capture information from your vehicle's On-Board Diagnostic (OBD) system to determine if your emissions system is operating properly.

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.


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


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