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Top 5 Reasons Why your Check Engine Light is On

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  1. Replace Oxygen Sensor/s
  2. Replace Catalytic Converter
  3. Replace Ignition Coil and Spark Plugs
  4. Tighten or Replace Fuel Cap
  5. Replace Thermostat
Top 5 Reasons Why your Check Engine Light is On

If you take nothing else from this article, remember that the check engine light is nothing to be ignored. The check engine light only goes on in your car when there’s a problem. Not every problem needs to be dealt with post haste, but it’s important to give the check engine light the respect it deserves.

The most common repairs indicated by the light range in price from as low as around $10 all the way up to around $1,100. Some repairs can be handled DIY, and others require a little more knowledge on the subject and a willingness to get your hands dirty.

Letting any of your vehicle’s problems drag on and on will almost surely cause the repairs to be much more costly when you finally get around to taking care of whatever the malady may be. Bring your vehicle into Ravenswood Auto in New Berlin, WI to have a diagnostic run and determine the reason your check engine light is on.

1.      Oxygen Sensor/s

Oxygen sensors help to get you the best mileage your car is capable of

It sounds like the oxygen sensor would be an important piece of equipment if you were scuba diving (and it is), but in this case, the oxygen sensor helps to maintain your vehicle’s optimal gas mileage and keep strain off the catalytic converter. Your fuel is burning rich if there’s less oxygen in the mixture and burning lean if there’s more oxygen in the mix. Rich means you’re producing more emissions (putting more strain on the catalytic converter) and wasting more fuel.

Repairing the oxygen sensor/s is a fairly small job as far as repairs go. It doesn’t take long and is a cheap repair to make (around $250 depending on the vehicle’s make, model, and year) considering the alternative, which is having to replace the overworked catalytic converter.

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2.      Catalytic Converter

The catalytic converter is the single most important part of your vehicle controlling the amount of pollutants in the exhaust.

Performance Influenced by:

  • Shoddy spark plugs
  • Leaky valves
  • Lead in your fuel
  • Rust or damage
  • Cracks in the head

This repair typically costs around $1,100 (depending on the make, model, and year of your vehicle), so you can see why the smaller repairs are a good idea to take care of ASAP when you notice the check engine light is on. Plus, you can’t pass a fuel emissions test without a functioning catalytic converter.

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Catalytic converter repairs are expensive because of the precious metals used to make them More Information

3.      Ignition Coils and Spark Plugs

Ignition coils and spark plugs help start your car

The ignition coils and spark plugs are part of what allows your car to start. The coils take the modest 12v charge from the car’s battery and transform it into enough power to create a spark in the spark plugs. The spark plugs then ignite the fuel under pressure created by the condensed space and pistons. From there, you’re off to the races.

Problems with your ignition coils and spark plugs can be recognized by the vehicle’s symptoms, which include misfiring pistons, rough idling, less power and acceleration, and worse gas mileage. Fixing these problems costs around $400 (depending on the make, model, and year of your vehicle and the extent of the bad parts). Misfiring pistons can lead to the O2 sensors not working in a closed loop, and that means your car will default to burning rich and putting unnecessary stress on the catalytic converter.

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4.      Gas Cap

This may be the one item on the list you’re hoping to encounter when you see your check engine light is on. A cracked or loose gas cap lets fuel evaporate and that triggers the check engine light. In the absence of weird vibrations, smells, or noises coming from your car when the light goes on, the changes are good that the problem is your gas cap. Stop where it’s safe and check out your gas cap.

If your gas cap is completely missing, come to Ravenswood Auto and grab a new one for under $15.

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Loose or cracked gas caps can set off your check engine light More Information

5.      Thermostat

Your car thermostat keeps your car from overheating

The thermostat in your car is what controls the engine’s temperature. The engine’s average operating temperature is approximately 180°F – 210°F. A failed thermostat stays in the position it was in when it dies. This means it either assumes the open or closed position.

A thermostat stuck in the open position releases a continuous flow of coolant. Doesn’t sound bad, but it affects the performance of the oil since the oil is engineered to provide the most lubrication when it’s warmed to a vehicle’s average operating temperature.

A thermostat stuck in the closed position stops any coolant from coming through to the vehicle’s engine. Within minutes, this can cause your engine to overheat and die.

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