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Reasons Why Your Car May Not Pass Smog

In California, you are required to pass a smog check in order to register your vehicle. A smog check is designed to check the emission levels of your vehicle and your vehicle’s exhaust system. The test checks the levels of hydrocarbons, carbon monoxides and nitrogen oxides that are emitted from your car. If your car has levels that exceed the allowable amount, you will fail the smog test. Typically, this occurs because your vehicle is running rough, has engine problems, or needs repairs to the exhaust system. But, there are some times when your car may fail, and it has nothing to do with the emissions that are being released. Here are non-emissions related reasons why your car may not pass a smog check. 

Your Check Engine Light is On

If your check engine light is on, your car will fail the smog test in California every time. Unfortunately, per California state law, a car repair shop is unable to turn you away simply because your check engine light is on. As such, they will test your car and you will fail. If your check engine light is on, bring it to a car repair center. Have the needed repairs made and have the light shut off before having a smog check. 

Your Car is Not Fully Warmed Up

Another common reason why your car may not pass the smog check is because your car is not fully warmed up. It is recommended that you drive your car for 20 to 30 minutes prior to bringing your car for a smog check. This allows your car to reach the proper fuel mixture level and combustion levels, both of which can throw off your emissions levels. 

You Recently Disconnected or Replaced Your Battery

When you disconnect or replace your battery, you can throw off the internal test monitors that are checked within your vehicle during a smog test. If you have recently disconnected or replaced your battery, it is recommended you drive your car for at least 100 miles and wait at least a week prior to having a smog check conducted on your vehicle. 

Your Car is In Need Of an Oil Change

The final reason why your car may not pass a smog check is because your car is in need of an oil change. If the oil in your car is dirty, the engine breathes in some of these dirty fumes. It then can give higher emissions readings during a smog test due to these fumes. Replace your oil prior to a smog check and then wait a few days before having your car tested. 

It is important to have all repairs made to your vehicle prior to having a smog check. If you are preparing to have your car smog checked, bring it to a trusted auto repair shop, such as us here at Morgan Automotive. Our car repair shop can evaluate your vehicle, make any needed repairs and get in ready for a smog check, helping to increase the odds of you passing. Book your appointment for auto repair with us today. 

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