You can take a number of actions to maintain your vehicle’s emission controls system:

• Have your emission control system inspected periodically (unless recommended otherwise by owner’s manual). More than 100 U.S. cities and counties have emission inspection programs designed to ensure that polluting vehicles are identified and repaired. Repairing a faulty emission control system can improve a vehicle's fuel efficiency by 6 to 7 percent. If there is no emission inspection program where you live, you should have a mechanic do a visual check of your vehicle's emission control devices to make sure they are in place and properly connected. Check your owner's manual to determine which parts of your emission control system are covered by warranty and for what length of time.

• Don't tamper with (e.g., remove, disable, or make inoperative) any element of your vehicle's emission control system. Not only is it illegal, but tampering with these elements increases your vehicle's emissions and reduces its overall performance and durability.
• If you have maintained your vehicle properly and it still fails the emissions test, you should have your catalytic converter checked. Be sure to get a thorough diagnosis of the engine and emission system before you replace the catalytic converter. Converter problems usually result from a problem in the engine management system. If you must replace a catalytic converter, make sure that the replacement label indicates that it meets the United States Environmental Protection Agency (EPA) requirements and is warranted to meet federal durability and performance standards. Also, check to see whether your vehicle's warranty entitles you to free repair of your converter. EPA regulations under the 1990 Clean Air Act Amendments require that catalytic converters be warranteed for eight years or 80,000 miles for 1995 and newer vehicles, and for five years or 50,000 miles for vehicles built before 1995. If you or your mechanic bypass an ineffective catalytic converter instead of replacing it, you are breaking the law.

Driving without using the car's air conditioning increases fuel efficiency by 2.5 miles per gallon, and that saves you money. If you must use air conditioning, proper maintenance has several benefits: it saves money, reduces the amount of chlorofluorocarbons (CFCs) in the atmosphere, and increases the life of your vehicle's air conditioning system.

Freon, the refrigerant used in most pre-1995 vehicle air conditioners, is a CFC. CFCs deplete the stratospheric ozone layer above Earth. This layer shields us from harmful ultraviolet rays that can cause skin cancer, cataracts, damage to the human immune system, and damage to crops and marine ecosystems. The United States stopped producing CFCs at the end of 1995. More than 150 other countries agreed to halt production of CFCs and other ozone-depleting chemicals by January 1, 1996. CFCs from vehicles can deplete the ozone layer if they are released into the air when car or truck air conditioners are serviced or when vehicles are scrapped or salvaged.

About half of 1993 model vehicles, 95 percent of 1994 models, and all vehicles built after 1995 have air conditioning systems that operate on non-ozone-depleting alternatives (such as HFC, hydrofluorocarbons). These newer vehicles pollute less.

When air conditioners in cars that use CFC R-12 are being refilled or repaired, federal regulations require that the service shops recycle the refrigerant instead of releasing it into the air. The refrigerant is filtered so that it can be recycled and reused. The service shop's capture or recycling machine should carry the seal of approval of a qualified testing laboratory, such as Underwriters Laboratories. Use of properly recycled refrigerant does not affect your vehicle's warranty. The refrigerant should also be removed from vehicles that are scrapped or abandoned and recycled.

If the refrigerant in your vehicle's air conditioning system needs to be replenished, always have a professional do it. You can damage your system if you improperly change it yourself. In addition, only certified mechanics can legally purchase refill cans of CFC. If your air conditioning system is leaking refrigerant, have it repaired — don't just refill it. This will both protect the environment and save you money.

If you own a pre-1995 vehicle and decide that you do not want to contribute to CFCs depleting the stratospheric ozone layer, you can easily convert your system from CFC R-12 to the safer R-134a. The average price to retrofit the air conditioning system is $50.00 to $150.00 more than the costs of other repairs.

A type l retrofit produces the same cooling power as before the retrofit, but costs more than a type II because more parts are replaced. A less expensive type II retrofit may be as simple as flushing out the CFC R-12, changing fittings and lubricants, and refilling with R-134a. The system won't cool as well, but this may be the right choice for an older, less valuable car.

Use this checklist to remind yourself of the maintenance activities that can reduce emissions and save fuel.

1. Read the owner's manual.
2. Follow the maintenance schedule.
3. Keep maintenance records.
4. Have your emission control system inspected regularly.
5. Use a high-quality gas cap.
6. Keep tires properly inflated.
7. Check belts and hoses.
8. Check the air conditioning system for leaks.
9. Change fuel filters and air filters regularly.
10. Change oil and oil filters as scheduled.
11. Check oil, transmission fluid, and radiator coolant regularly.
12. Replace the PCV valve and breather elements as needed/scheduled.

You can expect a number of benefits for your efforts:

1. Reduced air pollution and less environmental damage
2. Fewer health problems related to air pollution
3. Better vehicle performance
4. Longer vehicle life
5. Higher vehicle resale value
6. Money saved by preventing vehicle breakdowns
7. Money saved on fuel bills
8. Reduced dependency on foreign oil