Top 5 Reasons for a Check Engine Light

Phil's Pro Auto Service • October 15, 2023

When your vehicle’s internal computer system finds an issue with your engine or any other important part, it warns you by turning on the check engine light. This warning is indicated by the engine symbol on your dashboard lighting up red, orange, amber, or yellow. The cause of an illuminated engine light might be as simple as a loose gas cap or as complex as a damaged engine component. However, ignoring the problem can quickly lead to expensive repairs or inevitable vehicle failure.

Here are five of the most common causes of a check engine light and what you should do in the event that it comes on.

5 Common Culprits of a Check Engine Light

1. Loose Gas Cap 

Your gas cap helps to maintain the right pressure in your vehicle’s fuel delivery system and prevents vapors from escaping the fuel tank. When it is loose or missing, it may trigger a check engine light.

2. Oxygen Sensor Failure

If your vehicle’s oxygen sensor is malfunctioning, it won’t be able to determine how much oxygen is present in the exhaust, which means your vehicle won’t be able to deliver the correct amount of gasoline to your engine. If your engine is otherwise healthy, your vehicle may still continue to operate, but with fuel efficiency decreased by 40 percent , all while releasing harmful emissions into the environment.

3. Battery Issues 

A faulty or incorrectly installed battery can prevent your vehicle from starting and trigger a check engine light. Generally, vehicle batteries need to be replaced every three to five years, but exposure to harsh driving conditions and severe weather can negatively affect their lifespan.

4. Vacuum Hose Leaks 

Age and exposure to extreme temperatures can cause vacuum hoses to dry out and crack, resulting in leaks. When this happens, the engine warning light may turn on. In addition, if your vehicle’s idle speed suddenly rises or stays at an irregularly high RPM , a vacuum hose leak may be to blame.

5. Damaged Spark Plugs

A vehicle’s ignition system sends electric currents to spark plugs, which in turn send those currents directly to the combustion chamber, lighting the fuel-air mixture responsible for driving the vehicle. When a spark plug fails, it may cause the engine to misfire, reduce gas mileage, cause rough idling, and trigger the check engine light.

What to Do When Your Check Engine Light Turns On

While some check engine light issues can be resolved with simple troubleshooting, several others may be signs of serious engine failure and call for meticulous and in-depth professional repairs. If your gas cap, battery, and fuel levels are fine, but your engine warning light is still on, it’s worth consulting with a professional mechanic to avoid the risk of causing further damage to your vehicle and putting yourself in danger.

High-Quality Check Engine Light Diagnostics and Repair in Greeley, CO

At Phil’s Pro Auto Service, we provide top-rated, professional check engine light services in Greeley, CO that get down to the root cause of your vehicle’s issues. With advanced diagnostic and repair services performed by certified and experienced master mechanics, our shop is second to none when it comes to servicing all of your automotive repair needs in Greeley, CO.

To schedule an appointment or for more tips on avoiding check engine light issues, contact us today!

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