How Long Can You Drive With Check Engine Light On? A Guide

“How long can you drive with check engine light on?” is one common question, especially among new car owners. However, there is no direct answer to the question, as the distance to drive when the check engine light comes on may vary depending on the cause and severity of the issue. How Long Can You Drive With Check Engine Light On This complete guide provides in-depth information on why your check engine light is on and effective ideas on what to do, so read ahead. 

How Far Can You Travel With Your Check Engine Light On?

How far you can travel with your check engine light on depends on the severity of the issue with your car engine, but make sure you don’t drive farther than a few miles. When the light is on, it indicates that something is wrong with your engine’s functions. However, it is not something you should panic about, as it might be as simple as a loose gas cap. In fact, there are cases where the check engine light is on, but the car runs fine. Still, it could also mean a more severe issue with your vehicle.  Therefore, to be safe, you should quickly examine your vehicle for any noticeable changes in its sound or performance. You may also observe the car for indications such as high temperature, low oil pressure or a warning lamp. If it’s something you can quickly rectify, do so immediately; if not, visit your mechanic as soon as possible. 

– What To Do When the Check Engine Light Comes On

As soon as you notice that the check engine light of your car is on, the first thing you should check is the vehicle’s behavior and performance. Observe the car for any unusual sound, engine efficiency reduction, or anything strange. If you know your way around car engines, you can find a suitable parking spot, then check the motor oil level, the coolant, transmission fluid, the engine air filter, etc. Also, if the dashboard gauge indicates low oil pressure or an overheating of the engine, you need to immediately check the oil condition and the possible cause of overheating. If it’s something you can quickly correct, do so immediately. However, you can always decide to drive to your mechanic or find an expert close by to help check for possible issues in the vehicle. Furthermore, remember that though they are often mistaken to mean the same thing, the check engine light differs from the service engine light. The service engine soon light, which may also appear as service due, is more or less a reminder that your car is due for routine maintenance and servicing. 

– Meaning of Check Engine Light Coming On 

The check engine light is a warning signal indicating an issue with the vehicle’s engine or other essential vehicular components. It is sometimes referred to as the malfunctioning indicator light. The car’s Engine Control Unit (ECU) is in charge of detecting the fault and illuminating the light. Meaning of Check Engine Light Coming On Unlike in the past, most modern car designs have different actuators, monitors, and sensors that observe, regulate, and control the operations of the car’s engine components. The sensors and actuators connect to the ECU, which is the universal control for these features. So when there’s a deviation from the normal functionalities as automated by the manufacturer, the ECU causes the check engine light to come on Therefore, the check engine light warns the driver that one of the car’s engine processes is already deviating from the norm. However, only some of these indications are dangerous, as some may be simple and easily corrected by the driver. Also, we must add that the check engine lamp illuminates when you start the vehicle but goes off after a few seconds if the ECU detects no fault.

– Different Colors of Check Engine Light

The check engine light is usually either yellow or orange, though there are cases where it shows red. The yellow or orange check engine illumination indicates a minor issue. Therefore, you may continue driving as you attempt to observe unusual sounds or changes in engine performance.  In fact, if you know your way around car engines, it might be something you can easily fix. However, just because it’s a minor issue does not mean you should continue driving around without finding a solution to the illuminating check engine lamp. Indeed, the fault may not be detrimental to your engine, but it’s better to carry out precautional checks. Also, when the check engine light is on, this is not a time to aggressively step on the gas.  In fact, consider slowing down as you observe the vehicle’s performance and notice any unusual changes. Try to maintain the car at a steady speed, not more than 50 miles/hour. If you cannot detect anything unusual, you should visit your mechanic; as an expert, they will be able to find the cause of the problem and rectify it.  But what if the check engine light is shining red? If the check engine lamp is illuminating red and flashing, it’s often an indication that there is a severe problem with your engine or other car components. With that being said, you shouldn’t think twice before switching off your ignition. Stop the car and contact your mechanic or the nearest auto repair shop to prevent further harm to your engine.

– Driving With the Emission Light On

Generally, it is safe to drive with your emission light on; like the illumination of your check engine light, it poses no real threat to your safety. However, your car’s emission light coming on often means that there’s a fault with the vehicle’s emission control system.  Driving With the Emission Light On Your car’s exhaust system is likely polluting the air with fumes beyond the permissible federal specifications. Vehicles in such conditions will not pass a smog check or an emission inspection. So if this is the case with your car, it is advised that you contact your mechanic immediately. They will examine your car to diagnose and fix the problem. Afterwards, your vehicle should return to optimum condition with the emission light turned off. 

Why Is Your Check Engine Light Turned On?

Your check engine light is turned on due to several possible reasons such as an open or loose gas cap, but it’s not always that simple as it will also turn on when your vehicle’s catalytic converter is faulty or if there are issues with the spark plug.  Below is a detailed overview of the causes of the illumination of the check engine light. 

– Open, Loose, or Missing Gas Cap

Losing gas caps is one of the most common causes of the illumination of the check engine light. In fact, some cars like the Ford Escape may indicate “Check Fuel Cap” as the check engine light comes on. The gas cap is part of your vehicle’s EVAP system that prevents air from the atmosphere from mixing with fuel vapor, which may be harmful.  In addition, the fuel cap of your car is an essential part of the fuel delivery system; for one, it prevents gas spillage, reducing gas mileage. Moreover, it helps retain the pressure building up and retains fumes in the gas tank. Car users may forget to lock up their gas caps after refueling. Also, the fuel cap may be old and weakened, so it’s impossible to tighten it. In such cases, car owners just need to get a replacement for the loose gas caps to prevent gas spillage on roads. 

Bad Oxygen Sensor

A fault in the car’s oxygen sensor is another typical cause for the check engine light coming up. The oxygen sensor checks the level of oxygen not combusted in the car’s exhaust system. The vehicle’s onboard computer uses this information to regulate the mixing of air and fuel. A fault in the oxygen sensor may seem critical, but the car will continue to function.  However, the engine has little info to enhance the appropriate mixing of fuel with air, which results in the illumination of the check engine light. This may reduce fuel efficiency or even the misfiring of the car engines. If left unchecked and not rectified for an extended period of time, it may cause other harm to the vehicle. For example, it might negatively affect the spark plugs and catalytic converter and lead to poor fuel usage.  The leading causes of a bad oxygen sensor include water in the connector, contact of wires with the exhausts, which may melt it, accumulation of soots, broken wires, bent sensors, etc. Regardless of the cause of a malfunctioning oxygen sensor, car users should make sure to rectify the problem to restore optimum engine efficiency. 

– Malfunctioning Catalytic Converter

The catalytic converter is a critical component of the vehicle exhaust system. Its function converts harmful gasses and fumes, like carbon monoxide, into less harmful gasses, like carbon dioxide. Though the converter is not an advanced part of the car engines, if faulty, it may cause some issues with the engine.  Malfunctioning Catalytic Converter For example, a clogged converter will cause problems like overheating in the engine components. Also, it may reduce the car’s gas efficiency. An easy way to detect a bad catalytic converter is when you notice a rotten egg smell just after the check engine light comes on. When you notice this, visit your mechanic as soon as possible, as it may be expensive to replace a faulty converter. 

– Vacuum System Leakage

The vacuum system, consisting of the vacuum lines, throttle body, gaskets etc., is another critical component of car engines. When this system experiences faults, which is observed as a reduction in the release of harmful gasses and fumes, the check engine light illuminates.  Generally, vacuum pipes and hoses experience different temperature levels of heat and coldness. Therefore, over time there is a high tendency for wear and tear and even cracking, which results in leakages. Once there are leakages in the vacuum system, you will notice that your car will begin to rough idle, the car’s revolution per minute will start to fluctuate, and then the check engine light will turn on. 

– Worn Out and Faulty Spark Plugs and Wires

A defective spark plug or wires can also cause the illumination of the check engine light. Upon switching on the car ignition, the spark plug provides a spark that causes the mixing of air and fuel, producing power for the vehicle. With that being said, a fault in almost every component of the car’s ignition system may cause the check engine light to come on. Using a bad spark plug can cause the engine to misfire, which may be detrimental to other components. Also, there will need to be more energy to power the vehicle, or the vehicle will perform at a reduced efficiency. In addition, if you are yet to replace your spark plugs and your car has covered more than 100,000 miles, it’s high time to get the plugs replaced. You should also consider getting new spark plug wires. 

– Malfunctioning Gas Tank Pressure Sensor

A defective fuel tank pressure sensor is another typical cause of an illuminated check engine light. This device, sometimes called the EVAP or fuel vapor pressure sensor, sits atop the fuel tank and monitors the pressure build-up in the gas tank.  Malfunctioning Gas Tank Pressure Sensor As you drive your car, different chemical and mechanical reactions may result in pressure variations as the fuel is used to power the vehicle. When the pressure or fuel vapor in the tank is too high or too low, the sensor signals a warning light. The leading cause of a faulty fuel tank pressure sensor is corrosion, which affects its electrical components. 

– Defective Mass Air Flow (MAF) Sensor

The mass flow sensor is another crucial component of your vehicle. The effectiveness of this sensor may determine the performance of your car. It measures and controls the quantity of air that gets into the engine, regulating the air that mixes with fuel. If the air that mixes with fuel is not adequately regulated, it may cause the engine to stall or not start at all.  When the mass airflow sensor is faulty, the air that gets into the engine components is not regulated, which may be defective for the entire engine. Failure of the MAF sensor to function appropriately causes the check engine light to come on as the onboard computer detects fuel and air mixing issues in the engine. 

Can Driving with the Check Engine Light On Affect the Brake Lines?

Driving with the check engine light on can indicate a problem within the vehicle’s engine, but it does not necessarily affect the brake lines directly. However, it is essential to regularly inspect and maintain your car’s braking system to ensure optimal performance and safety. If you suspect any issues, it is recommended to consult an expert. Performing an expert review: replacing brake lines when needed can prevent brake failure and ensure a smooth driving experience.


Having read this article, you now know that you do not need to worry when taking a long road trip, and you notice that your check engine light illuminates. It’s your car’s way of detecting an issue with the engine, which may be minor and easily corrected. With that being said, let’s quickly summarize everything we discussed in the article. 
  • The illumination of your check engine light means that there’s a fault with your car engine or other vehicle components. However, it may be a minor problem that you can sort out yourself. 
  • The severity of the issue with your car engine will determine how far you travel when the check engine light comes on. As soon as you notice that the check engine light of your car is on, the first thing you should check is the vehicle’s behavior and performance.
  • Some of the reasons for your check engine light being constantly on include open  gas caps, a faulty oxygen sensor, a malfunctioning converter, leakage of vacuum system, worn out plug and wires, and bad tank pressure sensor.
  • Driving when the emission light comes on is safe, though your car excessively releases harmful gasses and fumes into the atmosphere. 
  • The check engine light may either be yellow or orange, which often means a minor issue, or appear red, indicating a more severe engine problem.
When your check engine light comes on, do not hesitate to review this article to guide you on the possible causes.
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