Check Engine Light: Causes and Solutions
Check Engine Light: Causes and Solutions

Check Engine Light: Causes and Solutions

10/02/2025
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Anh Tuan, owner of a Hyundai Mighty truck operating on the Hanoi – Bac Ninh route, shared: “The other day, while driving on Highway 5, the check engine light suddenly came on. Worried, I quickly pulled over and called my mechanic friend in Cau Giay. Fortunately, it was just a faulty oxygen sensor, not a serious problem.”

Anh Tuan’s experience is not uncommon for those who frequently use trucks. So, what is the check engine light? What causes it to illuminate? And how can it be fixed? This article will answer these questions.

What is the Check Engine Light?

The check engine light, also known as the malfunction indicator lamp (MIL), is part of the truck’s onboard diagnostic system (OBD). When this light comes on, it means the engine control unit (ECU) has detected a problem related to emissions.

Causes of the Check Engine Light Illuminating

There are many reasons why the check engine light might come on, ranging from minor issues to serious malfunctions. Here are some common causes:

  • Loose or Damaged Gas Cap: This is the most common, easiest to fix, but also the most easily overlooked cause.
  • Faulty Oxygen Sensor: The oxygen sensor measures the amount of oxygen in the exhaust to adjust the fuel/air ratio. When this sensor malfunctions, the engine will not operate efficiently, leading to increased fuel consumption and emissions.
  • Damaged Catalytic Converter: The catalytic converter treats harmful gases in the exhaust before they are released into the environment. When this component is damaged, your vehicle will not meet emission standards.
  • Faulty Spark Plugs: Spark plugs create an electrical spark to ignite the fuel in the engine. When spark plugs fail, the combustion process is inefficient, leading to increased fuel consumption and emissions.
  • Clogged EGR Valve: The EGR valve recirculates a portion of the exhaust gas back into the combustion chamber to reduce NOx (nitrogen oxide) emissions. When the EGR valve is clogged, exhaust gases are not treated efficiently.

How to Fix a Check Engine Light

When the check engine light comes on, you should take your vehicle to a reputable repair shop for inspection and timely repair. Early diagnosis will save you time, repair costs, and ensure safety on the road.

Note: Tampering with the electronic system on your truck can cause serious damage.

Check engine light on a truckCheck engine light on a truck

Check Engine Light Inspection and Repair Price List (Reference)

Service Price (VNĐ)
Diagnostic check 200,000 – 500,000
Gas cap replacement 100,000 – 300,000
Oxygen sensor replacement 1,000,000 – 3,000,000
EGR valve cleaning/replacement 500,000 – 1,500,000
Spark plug replacement 500,000 – 1,000,000

Tips to Prevent the Check Engine Light From Coming On

  • Regularly check and replace the gas cap when necessary.
  • Use good quality fuel of the correct type.
  • Maintain your truck regularly as recommended by the manufacturer.
  • Choose reputable and experienced repair shops.

Technician inspecting a truck's exhaust systemTechnician inspecting a truck's exhaust system

Frequently Asked Questions

Q: Is a flashing check engine light dangerous? A: A flashing check engine light usually indicates a serious problem. You should stop the vehicle immediately and call for assistance.

Q: Can I turn off the check engine light myself? A: You should not attempt to turn off the check engine light yourself. Doing so may cause you to overlook potential damage.

Q: My truck has a damaged catalytic converter, can I continue to use it? A: Continuing to drive with a damaged catalytic converter will pollute the environment and may result in fines.

How to Purchase at Xe Tai Ha Noi

For consultation and truck repair scheduling, please contact:

XE TẢI HÀ NỘI

  • Address: No. 1, Giai Phong Street, Hai Ba Trung District, Hanoi
  • Hotline: 0987.654.321
  • Website: xetaihanoi.edu.vn

Similar Products

Xe Tai Ha Noi offers a wide range of trucks such as: Hyundai, Hino, Isuzu,… with payloads from 1 ton to 15 tons. You can find more detailed information on our website: xetaihanoi.edu.vn

Conclusion

The check engine light is an important part of a truck’s safety system. Understanding the causes and solutions when the light comes on will help you protect your engine, save money, and ensure safety on the road.

If you have any questions, please leave a comment below or contact Xe Tai Ha Noi directly for detailed advice.

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