Blog Car Care Advice 6 Common Kia Check Engine Light Causes (+ How to Resolve It)
Car Care Advice

6 Common Kia Check Engine Light Causes (+ How to Resolve It)

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The Check Engine Light (CEL) is the last thing you’d like to see on your dashboard. Though worrying as it may be, understanding the common causes behind it can help you easily address this warning light.

But what should you do when the CEL appears?

We’ll answer this and other questions to help you deal with a Kia Check Engine Light.

This Article Contains:

Let’s get started!

6 Common Causes for the Kia Check Engine Light

The Check Engine Light is an amber or yellow light on Kia vehicles (and other Hyundai Motor Group makes). It indicates an issue with your car’s engine or emissions control system — a bad spark plug, O2 sensor, mass airflow sensor, etc. This warning light, along with other dashboard lights like the low oil pressure light, helps ensure your vehicle runs smoothly and safely.

The Kia Check Engine Light may appear for various reasons, both on a new vehicle and a pre-owned one. Let’s explore the most common ones:

1. Loose Gas Cap

A loose gas cap lets fuel vapors escape from the gas tank into the atmosphere. This gets detected by the EVAP sensor in the fuel tank, triggering the CEL even on a new vehicle with no engine problem. Contaminants can also enter the fuel tank through a loose gas cap and damage the fuel injectors.

2. Faulty Spark Plugs

A spark plug fouled with engine oil, coolant, or carbon buildup won’t ignite the air-fuel mixture properly. This leads to an engine misfire and an illuminated Check Engine Light.

3. Defective Mass Air Flow Sensor

Your Kia’s Engine Control Unit (ECU) uses the mass airflow sensor reading to adjust the fuel supply for combustion. A defective sensor can cause a lean or rich condition, leading to an engine misfire and a triggered Check Engine Light.

4. Bad Catalytic Converter

A clogged catalytic converter can increase the exhaust gas concentration in the engine, causing a misfire and an illuminated Check Engine Light. Symptoms like poor fuel economy and sluggish acceleration often accompany this. The catalytic converter can also get damaged from engine misfires due to other faulty components, like spark plugs, mass airflow sensor, etc.

5. Oxygen Sensor (O2 Sensor) Issues

The oxygen sensor upstream of the catalytic converter helps the ECU maintain the right air-fuel ratio in the engine. If it malfunctions, it may trigger the Check Engine Light and affect the fuel economy. The downstream oxygen sensor keeps a check on the catalytic converter efficiency and can also trigger the Check Engine Light upon developing a fault.

6. Vacuum Leak

A vacuum leak will allow unmetered air to enter the engine, leading to a lean fuel condition and an engine misfire, indicated by a lit CEL and a related trouble code. The leak can be caused by a damaged vacuum hose, intake manifold, or gasket.

Apart from these reasons, installing aftermarket products (e.g. a security alarm, additional lights, exhaust pipe, etc.) can also trigger the Check Engine Light. This happens because non-genuine Kia accessories can drain the battery or lead to a short circuit. So, if you’re buying a pre-owned vehicle, go for one with genuine Kia accessories.

But is it safe to drive your Kia Sorento or other models with the warning light? 
Let’s find out.

Can You Drive with an Illuminated Check Engine Light?

The answer depends on whether you have a steady or flashing Check Engine Light and if there’s also another active dashboard light.

A. Steady Check Engine Light

Yes, you can drive with a steady Check Engine Light, but it may aggravate your current problem.

It’s best to have a mechanic inspect your car soon to avoid damaging the engine and other components. Remember to check the gas cap before heading to your local Kia dealership to rule out the possibility of it triggering the CEL.

B. Steady Check Engine Light with Other Warning Lights

Pull over safely to the roadside and turn off the engine if other indicators, like the low oil pressure light, accompany the Kia Check Engine Light. You may require a service such as an oil change or fixing a leak. Contact a service center or the local Kia dealership for roadside assistance to prevent further damage.

C. Flashing Check Engine Light

You shouldn’t drive with a flashing Check Engine Light as it indicates a severe problem requiring immediate attention. Generally, engine misfires lead to this flashing amber or yellow light.  Get roadside assistance to tow your car to a workshop for inspection.

Next, let’s see how a mechanic would reset the CEL.

How to Reset the Kia Check Engine Light

Important: The Kia Check Engine Light should be reset only after addressing its underlying issues. Resetting the CEL without fixing the causes behind it will make it appear again, further damaging your car. 

Here are the steps a mechanic will follow to reset the CEL on your Kia Rio, Kia Niro, Kia Sorento, Kia K5, or any other model. They will generally use an OBD-II scanner but may also perform the reset by disconnecting the battery:

A. Using an OBD-II Scanner:

  1. Turn off the engine and find the OBD port.
  2. Connect the scanner to the port and turn the ignition key to the “on” position.
  3. Access the codes by pressing the “read” button on the scanner.
  4. Press the “clear” or “erase” button on the scanner to reset the trouble code.
  5. Turn the ignition key to the “off” position.
  6. Disconnect the scanner and start the engine to see if the warning light has disappeared.

B. Disconnecting the Battery:

  1. Switch off the ignition.
  2. Open your car’s hood and locate the battery’s negative terminal (or the negative connector).
  3. Disconnect the cable from the negative terminal. 
  4. Reconnect the negative terminal after about 15 minutes to see if the Check Engine Light has disappeared.

Before resetting the warning light, it’s crucial to diagnose what’s causing it — whether it’s just fumes escaping the gas tank, the spark plugs giving up, or something else.

Let’s see how much you’ll have to spend on the diagnosis.

How Much Does a Kia Check Engine Light Diagnosis Cost?

A Kia Check Engine Light diagnosis could cost you something between $95 and $138. However, this depends on your vehicle’s model, manufacturing year, and labor charges at the local Kia dealership or service center.

Are you confused between the Kia Check Engine Light and the Service Required Light?

How Is the Kia Service Required Light Different from the Check Engine Light?

The “Service Required” message comes up on Hyundai Motor Group (Kia’s parent company) vehicles when it’s time for their routine maintenance.

You may find it on:

The “Service Required” light, unlike the Check Engine Light, doesn’t necessarily indicate a problem that needs immediate attention. Your Kia may require new inventory for an oil change, tire rotation, or other services, depending on its mileage.

Wrapping Up

The Check Engine Light is your Kia’s way of communicating an emissions control system or engine problem. Addressing it promptly can help you avoid major repairs later.

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