Check engine light glows orange on a dark dashboard.

What does my check engine light mean and how do I fix it?

Last Updated : June 2026
Published By : Allstate

Key points

  • A check engine light indicates the vehicle’s computer has detected a problem it can’t fix automatically; a stored trouble code can be read with a diagnostic tool by a mechanic or OBD‑II scanner.
  • A steady light may signal a non‑urgent issue, while a flashing light indicates a serious problem that requires immediate attention to avoid damage.
  • Common causes include a loose gas cap, faulty sensors, ignition issues, catalytic converter failure, or battery/charging problems.
  • Ignoring the light can lead to more severe damage and higher repair costs; auto insurance generally does not cover routine check engine repairs.

A vehicle's check engine light can turn on for many reasons, ranging from a minor issue to a serious problem. Before trying to troubleshoot the problem, keep in mind what the check engine light signifies. As Consumer Reports points out, the check engine light means that the vehicle's electronic control system has identified a problem that it can't correct automatically.

After the light is triggered, a trouble code is stored in the car’s computer memory to properly identify the issue. This code can be read by a diagnostic tool carried by most auto repair shops. A qualified mechanic can read the code, diagnose the problem and in most cases repair your vehicle.

What does the check engine light look like?

According to motorist.org, some manufacturers and vehicle models have different warning lights to indicate the severity of the problem. The check engine light may either blink or remain constant – checking your specific car’s owner’s manual may help decipher what the light means. Check the image below for an example of what a check engine light looks like.

What does the check engine light look like?

According to motorist.org, some manufacturers and vehicle models have different warning lights to indicate the severity of the problem. The check engine light may either blink or remain constant – checking your specific car’s owner’s manual may help decipher what the light means. Check the image below for an example of what a check engine light looks like.

What does it mean if my check engine light is flashing check engine light vs. staying on?

If your check engine light is on, whether it’s steady or flashing, your car is telling you there’s a problem that needs to be fixed. However, there is a distinction between a flashing check engine light and a static one, according to AutoZone. The automotive parts retailer notes that while a steady light can indicate malfunctions that must be addressed, the vehicle may be safe to drive temporarily and might not require immediate repairs. However, a blinking light normally indicates an immediate threat to your vehicle’s parts and systems if you continue to drive. By checking your owner’s manual (or looking it up online), you may be able to decipher the specific blinking sequence, on certain cars. Here are some of the common culprits AutoZone mentions:

  • Catalytic converter failure
  • A severely misfiring engine
  • Problems with the vehicle’s speed sensors
  • Issues with the vehicle’s oxygen (02) sensors

AutoZone advises drivers to take their vehicle to a mechanic as soon as possible after the engine light starts flashing, even if it means pulling over and having the car towed.

Can I check my own check engine light?

You can check your own engine light with an onboard diagnostics (OBD) scanner. An OBD-II is the most up-to-date version of the technology – and it pulls codes from your vehicle's computer(s) to see what might be wrong with one of its components, according to Forbes. However, they note you should consider how much you’ll use the device, if nearby auto parts stores check codes for free and if you’re confident you can decipher complicated, model-specific codes before purchasing one.

Some shops or retailers may allow customers to borrow scanners and provide instructions and tips on how to get the correct reading. Either method can help you get a report that explains the error code and presents potential fixes. With this information, you’ll be more informed when you take your vehicle in for repairs.

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Common causes

The six most common causes of a check engine light, according to the Family Handyman, include:

  • A loose, damaged or missing gas cap
  • Failed, or failing, O2 sensors
  • Spark plug, wiring, or ignition issues
  • Catalytic converter failure
  • A faulty battery or charging system
  • Transmission problems

What to do if you’re driving and the check engine light appears

Consumer Reports identify a few things you can do if you're driving when the light appears. First, you can check your dashboard gauges and lights to see if there's a low oil pressure warning or if your engine is overheating. If you find either of these problems, it's best to pull over as soon as it's safe to do so. These problems can be serious and create a dangerous situation for you and your vehicle.

Also, if you notice performance problems with your vehicle, it's a good idea to reduce your speed and the demands on your engine.

Since the check engine light can point to many different issues, it's a good idea to have a qualified mechanic diagnose the issue as quickly as possible. That way they can fix the problem and get you safely back on the road.

What happens if I ignore my check engine light?

Ignoring a check engine light can cause more damage that eventually leads to more costly issues, according to CarMD. Their 2026 Vehicle Health Index reveals the cost to repair or replace the 10 most common damaged parts and systems that lead to a check engine light appearing. Here is their list of average costs (parts and labor) for inspection and replacement.

  1. Catalytic converter: $1,510.88
  2. Oxygen sensor: $286.87
  3. Ignition coils and spark plugs: $480.21
  4. Mass air flow sensor: $346.21
  5. Ignition coils: $256.45
  6. Evaporative emissions canister purge control valve: $172.12
  7. Fuel injectors: $572.27
  8. ABS wheel speed sensor: $271.11
  9. Thermostat: $323.59
  10. Spark plugs: $299.47

Does my car insurance cover check engine light repairs?

Generally speaking, car insurance doesn’t cover repairs for normal wear and tear as a vehicle ages. Unless the check engine light comes on as a direct result of a potentially covered incident, like a multi-vehicle crash, you probably will be unable to file a claim. Therefore, putting the problem off until a future date may only lead to more costly out-of-pocket repair expenses if other parts and systems begin to fail.

It's also worth noting you may need a car inspection for car insurance depending on the insurer and your specific circumstances. For example, if you purchase a used vehicle and want full coverage, the insurer might require an inspection to determine if it’s safe enough to drive. If the check engine light is on, you might fail the inspection depending on where you live.

Check engine light FAQs

Whenever a check engine light turns on, it's best to schedule an appointment as soon as you can. However, some lights may warrant greater urgency than others. A steady light may not be an emergency, says Consumer Reports. A blinking light, on the other hand, may indicate the engine is being overworked – such as towing something too heavy. Depending on your vehicle’s year, make and model, it may have red check engine light that means you should stop driving immediately.

An OBD-II scanner can clue you in on what's going on with your vehicle. Some repairs may be simple – for instance, replacing a gas cap. But other engine problems may need to be addressed by an experienced mechanic. Once those problems are addressed, the light should turn off.

Depending on the OBD-II scanner, you may be able to reset the code, which should turn off the light, according to Forbes. But if the problem isn't addressed, the light will likely come back on again.

Auto insurance typically covers sudden incidents. Depending on your coverage, these may include collisions, theft, fires, vandalism, hail damage and more. Maintenance repairs, however, are considered the driver's responsibility and are generally not covered by insurance.

Even if you’re able to diagnose the cause of your check engine light for free, the cost of repairs can vary widely depending on the root cause, according to Vehicle Health Index. For example, the average cost of replacing oxygen sensors is roughly $280, but the average cost of replacing a catalytic converter is more than $1,500.

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