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Five Reasons Why Your Check Engine Light Might Come On

Last updated on: March 8, 2021   # 

 

Your vehicle’s “check engine” light is designed to warn you of a potential problem. The best approach is to schedule an appointment with a licensed mechanic as soon as possible. With the use of advanced diagnostic equipment, they can quickly track down the source of your trouble. Let’s take a look at five most common reasons why your check engine light might come on.

 

1. Spark Plugs Have Worn Out

 

It’s only a matter of time before you’ll need to have your spark plugs replaced. While some of today’s spark plugs are rated to last for up to 100,000 miles, the life expectancy can vary greatly from one model to the next. As your spark plugs begin to burn out, expect to notice some obvious performance issues. Rough idling, hesitation, and hard starting can all indicate bad spark plugs.

 

Your vehicle’s onboard computer can tell when the spark plugs aren’t performing well. Multiple engine misfires will eventually trigger the check engine light. Don’t wait too long to visit a repair shop for a tune-up. Not only will your gas mileage take a big hit, but you also risk damaging the engine. While your vehicle is at the shop, the service technicians will also check the condition of the spark plug wires. Over time, hot engine temperatures can cause the insulation on the wires to break down.

 

2. Loose Gas Cap

 

It’s easy to forget to tighten your gas cap. This is especially true when you're rushing to get somewhere. If the check engine light has turned on after refueling, there’s a good chance your gas cap is loose.

 

While a loose gas cap may not seem like a big problem, it can be more serious than you think. The gas cap is a critical part of your vehicle’s evaporative emission’s system. When the gas cap is loose or missing, fumes are released into the atmosphere. This definitely contributes to environmental pollution. You should also consider the fact that you’re wasting gas.

 

If your gas cap isn’t properly sealing, it may be time to purchase a new one. Luckily, replacements are not expensive. After installing the new gas cap, your check engine light should turn off within a few minutes of driving.

 

3. Catalytic Converter Has Failed

 

Every vehicle is required by law to have at least one catalytic converter. The purpose of this component is to reduce harmful exhaust emissions. It features a honeycomb-structured ceramic material, which helps capture certain toxins.

 

On average, you can expect a catalytic converter to last for at least 10 years. However, poor vehicle maintenance often causes it to wear out much sooner than expected. For instance, worn spark plugs can cause raw fuel to collect inside the catalytic converter. Oil leaks can be just as problematic.

 

If your catalytic converter isn’t doing its job, the check engine light will be activated. A bad catalytic converter can also lead to a loss of power. The internal material can start to break apart, thus causing an excessive amount of exhaust pressure. In severe cases, your engine will stall.

 

Remember, a worn catalytic converter will ultimately cause your vehicle to fail its smog test. While new catalytic converters can be expensive, they do come with a confidence-inspiring warranty.

 

4. Vacuum Hose Leaking

 

A leaky vacuum hose can definitely cause the check engine light to come on. These lines help the engine to run smoother by lowering the amount of internal pressure. However, it’s not uncommon for vacuum hoses to spring a leak. High heat, gunk, and other factors can cause them to crack.

 

When a vacuum hose has broken, it allows unmetered air to enter the engine. You’ll experience many of the same symptoms that stem from worn spark plugs, including rough engine vibrations and backfiring. To fix the issue, your mechanic will need to replace the damaged vacuum line.

 

To prevent problems from occurring, it’s a good idea to have your vacuum lines regularly inspected for signs of wear. By getting the hose ahead of time, you can save yourself a lot of extra stress.

 

5. An O2 Sensor Has Failed

 

Every vehicle has a minimum of at least two oxygen sensors. By monitoring the amount of unburned oxygen in the exhaust system, they help the computer to maintain the correct fuel mixture. While too much fuel will cause the engine to run rich, too little fuel will lead to a lean-running engine.

 

Although O2 sensors are quite durable, harsh conditions cause them to gradually deteriorate. A failing O2 sensor will activate your vehicle’s check engine light. Issues, such as engine skipping and poor fuel economy, also may occur. Some people may suggest cleaning your oxygen sensors. However, this is not an effective solution. The best approach is to have them replaced by a certified mechanic.

 

Get in touch with Kadotani Auto Repair in Watsonville. We can determine why your check engine light is on.