Why Is My Check Engine Light On?

When your check engine light comes on it’s easy to assume the worst. Thoughts of expensive repairs and the hassle of life without your vehicle pop into your head. There are many potential issues that can cause the light to come on, so it’s important to get your car looked at by a technician as soon as possible even if it seems to be running normally. Taking care of the issue causing a check engine light quickly can save your car and wallet by preventing more serious damage occurring from an unaddressed problem.  At Matson Point S Tire and Auto, we can diagnose your check engine light and address the underlying issue, getting you back on the road.


What is the purpose of a check engine light?

The check engine light is a warning light on your dash that comes on when there is a problem with your vehicle. The light is triggered when your vehicle’s ECU (engine control unit) detects a malfunction within the various systems it oversees. There are a wide variety of reasons why the light can come on, ranging from something as simple as a loose gas cap to more serious issues like engine misfires and emissions problems.

How is a check engine light used to find an issue?

In order to determine the exact cause of the problem, the code causing the check engine light needs to be read from the ECU by a technician. Each code corresponds with a specific fault in the system that can be used to determine the exact issue. Based on the code, your technician will be able to tell you the likely reason the light came on. Read on to learn about some of the most common issues that trigger a check engine light.

Common causes of a check engine light

There are many different reasons a check engine light can come on, but the circumstances in this list are fairly common issues that may be causing it.

  • Catalytic converter and oxygen sensors

One common cause of a check engine light can be related to your vehicle’s catalytic converter and oxygen sensors. The catalytic converter is a device in the exhaust which is responsible for reducing the amount of toxic emissions from the engine. When the catalytic converter is not functioning properly (which could be caused by a clog), you can experience a check engine light

Failed oxygen sensors before and after the catalytic converter can also cause trigger a fault

Damaged or faulty catalytic converters can cause a check engine light.
  • Fuel cap

A loose, damaged, or missing fuel cap can cause a fault by triggering an evaporative emissions control code. The EVAP system in your car is designed to prevent gasoline fumes from escaping, which are harmful to the environment. If the check engine light comes on in your car, checking the tightness of the gas cap and look checking the seal is a quick way to determine if this is the problem.

A loose gas cap can cause a check engine light.
  • Mass airflow sensor

Another potential cause of a check engine light is a faulty or failed mass airflow sensor. The mass airflow sensor is responsible for monitoring the intake of air into the engine, which the ECU uses to determine the correct amount of fuel. When the mass airflow sensor is not functioning correctly, the engine will not run as it should, and the light may come on.

Blinking check engine light

If your check engine light is blinking, this is an indicator an active malfunction which is a much more serious issue that needs to be addressed as soon as possible. A blinking light could indicate a misfire, which can cause severe damage to your vehicle’s engine. If you encounter a blinking check engine light, pull over and do not continue driving until a technician look at it.

Addressing a check engine light

While these are some of the more common causes of a check engine light, there is no way to know for certain without a service technician interpreting the fault codes. Remember, ignoring the light and continuing to drive has the potential to damage your vehicle, leading to much more costly repairs.

Come visit Matson Point S Auto and Tire or schedule an appointment to let us diagnose your check engine light. Our skilled and friendly technicians will ensure your car is running as it should.

Our COVID-19 Safety Precautions


As we head into these uncertain times, the staff at Matson Point S Tire & Auto Repair is taking extra precautions to ensure that our client’s health and well being is our primary concern.

Our shop has always been one of the cleanest in the industry and until the the threat of the virus diminishes, we are taking new measures to ensure our customers and employees safety.

We are adopting new procedures that start with screening employees each morning prior to work to ensure they are healthy, anyone with symptoms will be sent home immediately and are to contact their physician.

We have sanitized our shop and will sanitize any touch points we may have on a client’s vehicle, this includes keys, steering wheels, switches, controls and handles. Our technicians and advisor staff will follow CDC Guidelines and will wear gloves not only to protect their hands but your vehicle as well, and have been instructed to sanitize their work areas, the shop restrooms, shop door handles, service counters, credit card equipment and of course their hands throughout the day.

Although we are confident our waiting area is clean, we would like to encourage our clients to leave their vehicles and not wait for them. Please take advantage of our free shuttle service in the Salt Lake area, as well as our loaner cars. If needed we can also pick-up and deliver your vehicle from your home or workplace.

As essential supplies in supermarkets dwindle, there is also growing concern in the auto industry that parts sourced from China and other areas may be in short supply as well. If you are contemplating essential repairs on your vehicle it might make sense to schedule them sooner than later. Or have us order the required parts for you and we will hold them until you are ready to come in.