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Toyota Corolla Check Engine Light On

Giving your car regular attention ensures that you and your family are safe when you move from point A to point B. As part of this care, your car requires regular inspection and servicing to ensure that it is in good condition. In many cases, the check engine light will tell you when the time has come.

A common reason for the check engine light in a Toyota Corolla is a loose or faulty gas cap. This cap seals the fuel system and maintains pressure. If it’s not sealed properly, it triggers the light. Tightening or replacing the gas cap can often turn the light off.

Car check engine indicator light on

One potential cause of a check engine light in a Toyota Corolla is a malfunctioning oxygen sensor. Think of this sensor as the car’s version of a doctor’s stethoscope, listening to your engine’s breathing and ensuring it’s running efficiently. If the sensor fails, it can lead to decreased fuel efficiency and increased emissions. Replacing the oxygen sensor will not only turn off the check engine light but also ensure optimal engine performance and fuel efficiency.

Another reason for the check engine light could be issues with the catalytic converter. The catalytic converter is like a guardian of the environment, transforming harmful exhaust gases into less harmful emissions. If it fails, it can lead to a decrease in performance and fuel economy, and even damage other parts of the exhaust system. Replacing the catalytic converter is necessary to resolve these issues, restore vehicle performance, and extinguish the check engine light.

Toyota Corolla Check Engine Light On

Car dashboard indicator lights

For most Toyota Corolla models, a steady glowing light means your engine needs your attention, but there is no severe problem. On the other hand, a flashing checking engine light technically implies that the vehicle is critical and needs attention immediately.

Your vehicle’s health is a priority. Just like a child, everything in a car is of utmost importance and should be constantly checked and serviced if need be. The engine is the core/heart of your vehicle, without which it cannot move. Any unattended damage to the engine can cause potential risk to your life, or at the very least, it can cost you a fortune in repairs.

Depending on your Toyota Corolla model, the check engine light located on your vehicle’s dashboard can be displayed in the form of a symbol of an engine, read “Check Engine,” or be a combination of both. A commonly misunderstood indicator in your Toyota Corolla, the check engine light is part and parcel of the onboard diagnostics system.

A check light engine illuminates in red or amber color, and it can be intimidating to see if it comes on, yet you do not know what is happening. Before you have a panic attack, the check engine light can mean various things and acts as a guide to identify your vehicle’s problem.

When driving in your Toyota Corolla and notice a steady glow from your check engine light; this typically means a less severe problem like a loosened gas cap.

Toyota Corolla Check Engine Light Blinking

Car check engine indicator light

A blinking Toyota Corolla check engine light typically indicates a more severe engine problem that requires immediate attention. It is advisable to contact a Toyota Corolla service department immediately as this will require expertise to resolve.

Cars are becoming more sophisticated. With this upgrading, car systems are more susceptible to failure, and therefore, repairs become more complex. Diagnosing what might be the problem with your Toyota Corolla can sometimes be challenging. Even making simple diagnoses like low tire pressure warnings and temperature warning lights may require expertise.

When the Toyota Corolla check engine light starts flashing, it is a warning sign that most drivers dread. Several reasons may cause this problem, and therefore, a proper diagnosis should be carried out to pinpoint the exact issue.

Today, car owners with automotive knowledge can quickly determine the problem using their own bought equipment from the comfort of their home. Using an Onboard Diagnostic scanner will help you detect your situation and, if possible, solve it simultaneously, cutting the costs of visiting a mechanic:

For the less knowledgeable Toyota Corolla Owners, if the check engine light comes on and the problem is more than a missing, loose, or broken gas cap, contact a certified Toyota professional. Do not ignore this warning sign as it can be fatal for your car if brushed off and unresolved.

Toyota Corolla Check Engine Light Meaning/Causes

Car mechanic looking under the engine hood

Again, there is no reason to panic when your Toyota Corolla check engine light turns on. An illuminated check engine light can spell little trouble like a loose fuel cap. But a flashing light is not something to be taken lightly. If you are familiar with check engine codes, you can easily DIY. If not, which most drivers are, you can as well take it to professional mechanics.

So, what are some of the reasons for your Toyota Corolla Check engine light to come on and stay on?

A Faulty Oxygen Sensor

As it is used to measure the amount of oxygen in your exhaust system, a damaged O2 sensor indicates excessive oxygen in the exhaust system. It, in turn, causes your engine to burn unnecessary fuel fast. The check engine light turns on to show that your Oxygen Sensor requires immediate replacement for fuel economy.

Bad Mass Airflow Sensor

You were wondering why your Toyota Corolla is consuming more fuel lately? Well, it might be an issue with the Mass Airflow Sensor (MAF). As part of the engine management system, the MAF measures the amount of air that enters the engine to determine the fuel needed to run your engine efficiently. An active check engine light could signal that the MAF needs replacement.

Copyright protected article by Know My Auto and was first published on May 5, 2021. .

Damaged Catalytic Converter

Toyota Corolla check engine light might be on because the catalytic converter is not performing its function of converting carbon monoxide produced during the combustion process to Carbon (IV) oxide. This mostly happens if you neglect and do not service your Toyota Corolla and, as a result, do not pass the emissions test. Your vehicle engine performance will decrease and negatively affect your fuel economy.

Faulty or Worn-Out Spark Plugs or Spark Plug Wires

A Toyota Corolla check engine light will illuminate because of bad spark plugs or plug wires. In the combustion chamber of your vehicle, the spark plug ignites an air and fuel mixture to make your engine run. Through the spark plug wires, the spark moves from the ignition coil to the spark plug. Damaged ones affect your vehicle’s overall performance and, in extreme cases, cause your engine to fail to start or continue to run correctly.

Toyota Corolla Check Engine Light Cold Weather

Cold weather with person wearing gloves and parka

Extremely cold temperatures can cause ice formation on sensitive parts of your vehicle – it can freeze the oil and hinder it from adequately circulating in the engine or cause blockage on the oil pipes. Other than that, the freezing temperature can cause a false reading on the electronic circuits.

Toyota Corolla Check Engine Light Gas Cap

Car gas cap cover

Before you decide to make that trip to the mechanic, you might want to check for a loose, broken, or missing gas cap first. This is one of the primary reasons that can cause your check engine light to turn.

The gas cap serves multiple purposes, including preventing gas from being released when the vehicle is not in use. You can quickly lose fuel through evaporation when you have a missing, damaged, or loose gas cap, which is why your check engine light will alert you to the issue.

While replacing a gas cap is not expensive, car maintenance can become costly if not attended to, as you will be forced to make more trips to the filling station.

Toyota Corolla Check Engine Light Oil Change

Female checking engine oil dipstick

An illuminated engine light coils also mean that your vehicle needs an oil change. It can either be because the oil is too dirty or the oil is not enough to flow throughout the engine. Once you notice a check engine light on your Toyota Corolla. It is advisable to check your oil before you rule it out.

Toyota Corolla Check Engine Light Reset

Car dashboard check engine indicator light on

As long as you have resolved the issue, your check engine light will shut itself off. Depending on the severity of the case, let us say a lost cap; once you fasten it, you are good to go. You will first require a quick diagnosis for more complicated issues like the catalytic converter or mass airflow sensor. However, once resolved, the check engine light will automatically turn itself off.

Apart from letting it go off by itself, you can also turn your ignition on and off several times in a row or disconnect and reconnect your battery. It is also possible to reset it yourself using an OBD II scanner.

What if you think you are done with the problem, but a few days later, are back to square one, or the light never goes off. In this case, you still have a problem, and it’s advisable to schedule an appointment with the Toyota Service Center.

The copyright owner of this article is and was first published on May 5, 2021..

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KnowMyAuto is the sole owner of this article was published on May 5, 2021 and last updated on .