Why Would a Car Fail An Emissions Inspection? A blog about why your car would fail emissions and what you can do to fix it.
Your vehicle may have failed its inspection due to an issue with the emissions system or because of a faulty light. There are several common reasons why a vehicle fails emissions testing, according to the New York State Department of Motor Vehicles (DMV):
- A faulty gas cap
- Gas Cap Issue
- Catalytic Converter Issue
- A crack in your car’s exhaust system
- Exhaust leaks (e.g., at the manifold)
- An issue with one or more catalytic converters
- Worn spark plugs, wires or coils
- An internal vacuum leak
- Oxygen sensors in need of replacement
Faulty lighting — headlamps and turn indicators must be bright enough for oncoming drivers to see clearly, while brake lights and tail lamps must be visible from at least 500 feet away.
Check your gas cap
A faulty gas cap is the most common reason for a failed emissions test. This component’s primary function is to keep gas fumes from escaping your car’s fuel tank. If it’s cracked or has any other type of damage, it will no longer seal properly and your vehicle will fail its inspection.
You can see if this is the issue by looking for a malfunction indicator lamp (MIL), also known as the check engine light. If this light comes on when you drive, it means there’s a problem with your car’s emissions system. The engine control unit (ECU) has detected an issue and turned on the MIL to alert you.
If your emissions system does have a problem, try tightening the gas cap before you do anything else. Assuming the gas cap isn’t damaged or cracked, this may resolve the issue, turning off the MIL and allowing you to pass inspection.
Make sure the test was accurate
The first step is to double check that the machine actually recorded an accurate reading. According to Illinois EPA, some common reasons for erroneous readings include:
- The gas cap wasn’t secured properly or at all
- The vehicle was idling too long before testing
- You pumped gas right before testing
- You had recently filled your tires with air or added windshield wiper fluid
- You had recently washed your car If any of these apply to you, it might be worth getting a second opinion.
The emissions test is a necessary evil for many drivers. It’s an inconvenience, but it’s also a helpful safeguard in the fight against air pollution.
It’s important to remember that even though your vehicle may have failed its emissions test, it doesn’t necessarily mean there’s a major problem. Minor issues can cause a car to fail, and it’s possible that the technician made an error during the testing process. With the help of an expert mechanic, you should be able to get behind the wheel again before long.