Check engine light: An overview
The check engine light (also called CEL or Malfunction Indicator Lamp) is part of your vehicle's advanced Onboard Diagnostics system, which continuously monitors your engine, transmission, exhaust, and other component operations for inefficiencies and notice-day emissions problems.
When the OBD-II system determines that the vehicle is operating outside an acceptable range with respect to performance or emissions, it will activate the check engine light on the vehicle's dashboard. A steady check engine light usually indicates a minor or moderate problem, such as a loose gas cap or sensor malfunction. It should be diagnosed in a timely manner to prevent vehicle deterioration.
A flashing check engine light indicates a significant issue, such as misfiring cylinders or catalytic converter problems. In this case, further driving of the vehicle can jeopardise engine or exhaust system conditions and could pose safety problems.
If the light is ignored, it may lead to problems such as excessive fuel usage, expensive repairs, or emissions issues. Getting the vehicle promptly diagnosed with an OBD-II scanner or through a certified technician is important for maintaining vehicle health and safety.
Common causes of a check engine light
If the check engine light illuminates on your vehicle’s dashboard, it can be the result of one or multiple reasons.
Here are some of the most common reasons for your vehicle's CEL coming on and the explanation so that you can determine which one applies:
Loose or faulty gas cap
Believe it or not, a loose or faulty gas cap is one of the most common and simple fixes for the check engine light. The gas cap seals the fuel system, maintaining pressure and preventing vapours from escaping the system.
If it is not tightened properly, or the rubber gasket is damaged, the system detects a vapour leak and creates the OBD-II alert. The fix is simply to make sure the cap is tightened until you hear a click sound.
Oxygen (O2) sensor malfunction
The oxygen sensor tracks the level of unburned oxygen in the exhaust system and relays the data to the vehicle’s computer to adjust the air-fuel mixture. Once it fails, the engine will operate inefficiently, burn more fuel, and emit higher levels of pollution. Driving with a faulty O2 sensor can damage the catalytic converter, one of the most expensive components to replace.
Faulty catalytic converter
The catalytic converter converts harmful emissions (such as carbon monoxide, nitrogen oxides, and hydrocarbons) into less toxic gases. The part can clog or fail as it ages, due to poor fuel quality, or from neglected misfiring.
A faulty catalytic converter will likely cause poor fuel economy, a loss of power, and a lingering sulfur smell through the exhaust. The only option is to replace a faulty catalytic converter; however, ignoring the problem can lead to extensive engine damage.
Bad spark plugs or ignition coils
The spark plugs and ignition coils are responsible for igniting the fuel-air mixture in the engine cylinders. If either fails, you will start to experience rough idling, poor acceleration, and misfiring, which causes the check engine light to flash.
Replace your spark plugs when they start to wear (every 40,000–60,000 km), and ensure that your ignition coils, which will continuously be working, are not malfunctioning. If you can prevent replacing the coils, you can stretch the lifespan of any engine and improve less performance.
Mass Air Flow (MAF) sensor issues
The Mass Air Flow (MAF) sensor indicates the amount of incoming airflow into the engine, allowing the computer to adjust the fuel amount accordingly. A dirty or defective MAF sensor can lead to rough idling, sluggish acceleration, and stalling. Using an approved air filter and keeping the entire intake system clean can aid in sensor accuracy. If the problem persists, the MAF sensor may require cleaning or replacement.
Vacuum Leaks
Vacuum leaks occur when air escapes from cracked hoses or loose intake components. Vacuum leaks disrupt the ideal air-fuel ratio and can cause rough idling, engine racing, and stalling. Mechanics can find leaks in the system by performing smoke tests. Keeping hoses checked and replacing them during routine service can help prevent problems from occurring.
EGR (Exhaust Gas Recirculation) System Problems
The purpose of the EGR system is to reduce nitrogen oxide emissions by recirculating a portion of the exhaust gas back into the engine.
Carbon build-up in the system or a faulty valve can cause the EGR system to fail, triggering the check engine light. Regularly cleaning or replacing EGR system components will help maintain emission control and ensure the engine operates efficiently.
What to do when the check engine light comes on
Seeing the check engine light can be stressful, but knowing how to respond calmly can help prevent more significant problems. Here’s how to handle it safely and wisely:
Remain calm and do not panic
The initial thing to do is remain calm. The check engine light does not mean you are doomed. In many circumstances, a check engine light is simply an indication of a minor issue that is not a threat to your safety. But without addressing the check engine light, there is a chance you could have a major problem later.
Check if the gas cap is loose or damaged
Find a safe place to pull over and inspect your car’s gas cap. Tighten the gas cap to the proper specification and ensure you hear a click. If the gas cap was loose, it may simply be that after driving, it clears itself on its own. However, if the check engine light remains illuminated, it is most likely pointing to a more complicated issue.
Notice whether the light is flashing or steady
A solid light generally indicates a non-urgent condition that allows you to drive safely until you can have it serviced. If the light is flashing, it requires immediate attention, as it indicates an engine misfire or that something potentially hazardous is about to occur.
Slow down and don’t be discouraged if the light is flashing
If you have to drive with a flashing light, slow down, drive gently, and avoid high engine revs. This will reduce the strain on the engine and keep it running until you can reach a mechanic or a safe place.
Scan with an OBD-II reader for diagnostic trouble codes
An OBD-II reader will register DTC, Diagnostic Trouble Codes that explain what's causing your CEL. You can purchase a low-cost portable scanning device, which may utilise your smartphone as an interface, or refer to service manuals to determine if these faults are minor or severe before visiting the workshop.
If your car is indicating a loss of power, or a strange noise, excessive smoke, or the CEL is flashing, then you need to stop ASAP and call a professional. Ignoring these indications could cause irreversible damage to your engine and make it unsafe to drive.
How to prevent check engine light issues
The best way to avoid the check engine light is to practice proactive maintenance, along with good driving habits. Effective actions can reduce the likelihood of these types of issues.
Regular vehicle maintenance and service
Regularly servicing your vehicle ensures that the engine and its systems function properly. Consistent oil changes, inspections at recommended intervals, and the use of original parts add up to savings in your wallet and a lower chance of OBD-II notifications.
Keep sensors clean
Dirty and carbon buildup on them can alter the performance of those sensors, so it is important to periodically use quality filters and have the intake and exhaust systems cleaned. A clean sensor will provide accurate data, which results in better overall engine performance.
Use quality fuel
Using low-grade or adulterated fuel will form carbon deposits on the sensors and impact the combustion cycle. You should always ensure that you fuel your vehicle at pumps that offer quality fuel.
Therefore, check the engine oil rating recommended by your vehicle's specific manufacturer for your specific engine. Using quality fuel and engine oil will result in longer lifetimes for the vehicle’s components.
Replace filters and spark plugs as recommended
Air filters and spark plugs will wear out over time and should be replaced according to the manufacturer's service intervals. When a filter gets clogged, air can no longer flow as intended, and a worn spark plug can produce a misfire that will trigger the CEL. Replacing the ignition unit and filters prevents the ignition system from becoming inefficient.
If you notice minor vibrations, an intermittent drop in power, or an irregular idle in your vehicle, address the issue immediately. Minor performance issues usually occur before engine damage occurs or the CEL is illuminated. Taking action on the minor issue you see developing can save you time and money on more significant repairs related to the issue.
Bottom line
The check engine light is your car’s way of telling you something isn’t quite right. It doesn’t always mean a serious problem, but ignoring it can lead to costly repairs or lower fuel efficiency. Knowing the difference between a steady and flashing light, doing some basic checks, and using an OBD-II scanner can help you stay on top of things.
With ACKO Drive service centres operating across major cities, taking care of your car is simple and hassle-free. Simply book a service slot online through the ACKO app or the ACKO Drive website, and our team will handle everything, from inspecting your car’s engine and sensors to ensuring everything is running smoothly.
Keeping up with regular maintenance, using high-quality fuel and oil, and relying on professional help will ensure your car remains safe and reliable for a long time..
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