What is the icon for the engine light?

The engine light icon on a vehicle’s dashboard is a stylized silhouette of an engine, typically amber, and is commonly called the Check Engine Light or the Malfunction Indicator Lamp (MIL).

This article explains what the icon looks like, why it appears, how to respond, and how interpretations may vary across car brands and regions.

What the icon looks like

In most modern cars, the Check Engine Light is a small, amber-colored symbol depicting a simplified engine block. The design can vary slightly by manufacturer, but the general idea is a side-on or schematic engine outline with a few lines suggesting exhaust. The color (usually yellow or orange) is chosen to grab attention without signaling immediate danger the way a red warning light would.

Common triggers for the MIL

Several issues can cause the Malfunction Indicator Lamp to illuminate. The following list covers some of the most frequent, ranging from simple fixes to more complex problems.

• Loose or faulty gas cap allowing fuel vapors to escape


• Faulty oxygen sensor or mass airflow sensor


• Malfunctioning catalytic converter or emissions-control components


• Spark plugs or ignition coils that are worn or failing


• Evaporative emissions system leaks or valve problems


• Suspicious fuel injector or fueling system faults


• Electrical wiring or connector issues in the engine-control system

Note that a MIL coming on does not always mean an imminent breakdown; many faults are emissions-related or intermittent. However, the underlying issue should be diagnosed and repaired to prevent further damage and ensure optimal fuel efficiency and emissions performance.

What to do when the light comes on

When the MIL illuminates, you should balance safety with timely diagnostics. The following steps provide a practical approach for most drivers.

Flashing vs steady indicators

A flashing check engine light typically signals a severe problem, such as a misfire, that could damage the catalytic converter. If you see a flashing light, pull over safely as soon as possible and seek immediate service. A steady light indicates a fault has been detected but is generally less urgent; you should still diagnose and address it promptly to avoid potential engine damage or reduced efficiency.

Proceed with these steps to diagnose and address the issue:

1. Safely pull over and assess your driving situation. If you’re under heavy load, in traffic, or the engine is behaving unusually (rough idle, stalling, loss of power), consider stopping at a service center rather than continuing.


2. Check the gas cap. If it’s loose or damaged, reseal or replace it and drive a short distance to see if the light resets.


3. Note any symptoms you’ve observed (rough idle, reduced power, unusual noises) as these can help pinpoint the issue when you seek help.


4. Have the vehicle scanned for trouble codes. An OBD-II scanner (or a free scan at many auto parts stores) will retrieve codes that point to the likely system or component causing the fault.


5. Take your vehicle to a qualified technician for diagnosis and repair based on the codes and symptoms. Do not ignore persistent MILs, especially if a code indicates emissions or engine faults that could affect safety or compliance.

Even if the light goes off after a drive, a stored code may remain, and the issue can reappear. A diagnostic check is recommended if the MIL returns or if you notice performance changes.

Brand variations and terminology

While the generic icon is widely recognized, some brands use different terminology or alternate icons. In many markets, the term Check Engine Light or MIL is used interchangeably with phrases like Service Engine Soon or Malfunction Indicator. Some regional vehicles emphasize emissions-related warnings more clearly, and the icon style may vary slightly in shape or shading.

Regional and model differences

Older vehicles or certain brands may display a specific Service Engine Soon icon or a similar warning for non-emission faults. As vehicle diagnostic systems have evolved, the underlying meaning remains the same: an issue detected by the onboard computer that warrants inspection and potential repair.

Summary

The engine light icon is a stylized engine silhouette, usually in amber, known as the Check Engine Light or MIL. It signals that the vehicle’s onboard diagnostic system has detected a fault in the engine or emissions-control systems. Common triggers include loose gas caps, sensor faults, and emissions component issues. If the light is flashing, treat it as urgent and seek immediate service; a steady light warrants a diagnostic soon. Always consult a qualified technician to interpret codes and perform necessary repairs, and remember that brand variations may alter the exact icon or wording used on your dashboard.

What does a check engine light icon look like?

A check engine light typically looks like a yellow or orange engine icon on your dashboard, though some cars may display the words "CHECK ENGINE" or "SERVICE ENGINE SOON" instead. The light can be a steady glow or a flashing or blinking light, which indicates the severity of the problem.
 
This video explains what to do when your check engine light comes on: 57sThe_Car_MomYouTube · May 12, 2023
Appearance and behavior

• Shape: An outline of an engine is the most common symbol, according to Cars.com and WyoTech. 
• Color: The light is often amber, yellow, or orange. It can also be red in some cases, depending on the severity of the issue. 
• Text: Some vehicles may have "Service Engine Soon" or "Check Engine" written out on the dashboard instead of, or in addition to, the engine icon. 
• Steady vs. flashing:
  • A steady light indicates a less urgent problem, such as a loose gas cap, and usually requires a visit to a mechanic when convenient. 
  • A flashing or blinking light indicates a severe problem, such as a major engine misfire, and requires immediate attention to prevent serious damage. 

This video shows what to do when your check engine light is flashing: 1mGoTechYouTube · Apr 9, 2020

Is it okay to drive a car with the engine light on?

You can likely drive with a solid check engine light, but a flashing light means you should pull over immediately and seek professional help. If the light is solid, drive cautiously to a mechanic and avoid heavy driving until the issue is diagnosed, as it could be a minor problem like a loose gas cap or a more serious one like a faulty catalytic converter. 
If the check engine light is solid:

• Drive cautiously: It's generally safe to continue driving, but reduce your speed and avoid hard acceleration, heavy loads, or towing. 
• Check the gas cap: Pull over when it's safe and ensure your gas cap is tight. Tighten it and continue driving; the light may turn off after a few trips. 
• Look for other symptoms: Pay attention to any changes in your car's performance, such as strange noises, loss of power, or smoke. If you notice any, pull over as soon as possible. 
• Schedule a diagnostic check: Make an appointment to have the car scanned by a mechanic as soon as you can. 

If the check engine light is flashing:

• Pull over immediately: A flashing light indicates a serious problem, such as a misfire, that could cause significant damage to your engine or catalytic converter. 
• Turn off the car: Once you've pulled over to a safe location, turn off the engine. 
• Do not drive: Do not attempt to drive further. Have the vehicle towed to a repair shop for an inspection. 

What is the first thing to check when the check engine light comes on?

The first thing to check when your check engine light comes on is your gas cap. Make sure it's tightened securely, as a loose cap is a common cause for the light to turn on. If the light remains on after you've tightened the cap, check your dashboard for any other warning lights like low oil pressure or overheating and pull over safely if you see any. 
Step 1: Check the gas cap 

• Unscrew the gas cap and then re-tighten it until it clicks. 
• A loose or damaged gas cap can cause a vapor leak, which triggers the light. 
• After tightening, the light may not turn off immediately. You may need to drive for a while for the system to reset. 

Step 2: Check for other signs of trouble

• Look at your dashboard to see if any other warning lights have come on, such as a light for low oil pressure or a temperature gauge that is in the red zone. 
• Listen for any unusual sounds coming from the engine or notice if there are any changes in how the car is driving, like a loss of power. 
• If you see other warning signs or notice performance issues, pull over as soon as it is safe to do so and turn off the engine. 

Step 3: Get the diagnostic code read 

• If the light is still on and there are no immediate signs of a serious issue, your next step is to get the car's trouble code read. 
• Most auto parts stores offer free diagnostic services where they can plug a code reader into your car's port and tell you what the issue is. 
• This code can provide clues to more complex problems like issues with an oxygen sensor or catalytic converter. 

What is the most common reason for check engine light?

The most common reasons for a check engine light are a loose or faulty gas cap, a failing oxygen sensor, or bad spark plugs. Other frequent causes include a malfunctioning catalytic converter, a dirty mass airflow sensor, or vacuum leaks. 
Common causes
This video explains the top reasons for the check engine light: 47sThe Auto BrainYouTube · May 5, 2025

• Loose or damaged gas cap: A loose or cracked gas cap can allow fuel vapors to escape, triggering the light. This is often one of the easiest fixes. 
• Failing oxygen sensor: The oxygen sensor measures the amount of oxygen in your exhaust. If it's failing, it can lead to a drop in fuel efficiency and turn on the light. 
• Bad spark plugs or ignition coils: Worn-out spark plugs or a failing ignition coil can cause engine misfires, leading to poor performance and triggering the light. 
• Faulty catalytic converter: This component converts harmful exhaust gases into less harmful ones. A failing catalytic converter can cause a significant drop in fuel efficiency and performance. 
• Dirty or faulty mass airflow sensor (MAF): The MAF sensor measures the amount of air entering the engine. Contamination or a malfunction can cause the light to come on. 
• Vacuum leaks: Cracks or leaks in vacuum hoses can disrupt the air-fuel mixture and trigger the light. 

What to do

• First, check that your gas cap is on tightly and is not damaged. 
• If the light remains on, you can use an OBD-II scanner to read the specific code from your car's computer to diagnose the problem more accurately. 
• Some issues, like a loose gas cap or minor vacuum leaks, can be fixed yourself. Others, like a failing catalytic converter or oxygen sensor, may require a professional mechanic.