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In Idaho, most gasoline-powered vehicles, model year 1981 and newer, and diesel-powered vehicles over 5 model years old are required to undergo emissions testing every two years. When you pass emissions, you will receive a Vehicle Inspection Report and will be able to continue with the registration process. Unfortunately, you may not always pass emissions on the first attempt.

6 Reasons Why a Vehicle Fails Emissions

If your vehicle appears to be operating smoothly, failing an emissions test will come as quite a shock. You are probably wondering just what the heck happened. These are six common reasons why a vehicle will fail emissions, and what can be done to fix it.

  1. You are past due for an oil change. When you delay an oil change, it could cause you to fail an emissions test. Clean oil contains fewer hydrocarbons and makes for a cleaner engine- which means a cleaner emissions output. This is an easy fix, get the oil changed, and don’t delay it again. If you are unsure how often you should be changing your oil, you can look in your vehicle owner’s manual for the answer. Or, you can ask one of the experts at Meridian Automotive.
  2. You have a rich air/fuel mixture. A rich air/fuel mixture will often cause a failed emissions test. This problem is usually a result of a defective oxygen sensor or faulty injectors. So, if you fail emissions, have these components inspected and changed if necessary.
  3. You have worn spark plugs. Faulty or worn spark plugs leads to increased emissions because of incomplete combustion. Inspect them regularly and replace them when necessary
  4. You have a loose or leaking gas cap. This is an issue that is easily corrected. First, check to see if the cap is on tight enough. If not, tighten it. Often, this is one of the first things they check during an emissions test to make sure you don’t fail unnecessarily. If it is on tight enough, it may, however, still leak which could also result in a failed emissions test. If you do have a gas cap leak, simply have it replaced with a gas cap that will properly seal the tank.
  5. Your air filter is dirty. A dirty or clogged air filter could cause high levels of hydrocarbons and can be responsible for a failed emissions test. Most manufacturers recommend changing the filter once every twelve months or every 12,000 miles. If you don’t remember the last time you had your air filter changed, it may be wise to do it before your emissions test to help avoid failing.
  6. Your “check engine light” is on. A vehicle with a check engine light that is on will fail emissions immediately. The most common reason a check engine light comes on is because of a broken oxygen sensor.  You should never delay repair when your check engine light comes on, or what starts out as a minor, affordable problem could turn into a serious and expensive problem.  If your check engine light is on, have one of the automotive repair professionals at Meridian Automotive run a diagnostic test and fix your vehicle before you try and bring it in for emissions testing.

If you have recently failed emissions, we invite you to bring your vehicle into Meridian Automotive. We are a highly qualified emission repair and retest facility. We can diagnose the reason why your vehicle failed emissions and repair the vehicle, then, re-test vehicle to get you an emissions certificate. Call us today (208) 297-5573 or schedule an appointment online.