2021 Kia K5 Has A Check Engine Light

Troubleshooting the Check Engine Light in Your 2021 Kia K5: Common Causes and Solutions

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Reviewed by
Bo Fader
Written by RepairPal Car Genius
Updated January 14, 2025
0%
40% chance it's the
Emissions System
0%
60% chance it's
Something else
The most common reasons a 2021 Kia K5 has a check engine light are an emissions system component, a sensor, or a catalytic converter.
  • Emissions System: A faulty emissions system component, such as an oxygen sensor or EGR valve, can lead to increased emissions and trigger the check engine light.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a 2021 Kia K5 has a check engine light?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

A faulty oxygen sensor is one of the most common causes of a check engine light. Symptoms may include a decrease in fuel mileage, hesitation or misfiring from the engine, rough idling or even stalling. A faulty sensor may cause the vehicle to fail an emissions test.

Any time there is an emissions fault the check engine light will be displayed. The purpose of the check engine light is to inform the driver that an emission related fault has been found, and that there are on-board diagnostic (OBD) trouble codes stored in the powertrain or engine control module. Additionally, since the emissions systems are so intertwined into engine control and transmission control systems, symptoms may include nearly any sort of drivability concerns. This may include harsh shifting, failure to shift, hesitation on acceleration, jerking, engine failure to start or run, loss of power, or any number of other drivability issues.

Due to the nature of electrical systems on modern vehicles, the range of problems these can cause are nearly limitless. However, there is a way to categorize them in two ways. Permanent and intermittent problems. Permanent problems appear and remain. This may be the vehicle will not start, the radio does not work, or the door chime will not turn off among many, many others. These problems are more straight-forward to diagnose since they present themselves at all time. This means there will always be a fault to find. Intermittent electrical problems, however, can be difficult or impossible to locate, since they appear then disappear without warning. The best case scenario for an intermittent issue is when replicating the problem is easily accomplished and understood. This allows a technician to make an issue semi-permanent, allowing them to find the fault. Other issues that come and go without warning and cannot be replicated on demand must occur when the technician is servicing the vehicle, otherwise there is no problem to correct. It is most important to understand that electrical system faults always require inspection, and can include the vehicle working in any manner, or not working at all.

Like we noted in the last section, general diagnosis symptoms are the most vague of the bunch. There are several diagnostic spectrums, electrical diagnosis, drivability diagnostics, engine diagnostics, transmission diagnostics, and the list could continue for about 5 or 10 more spectrums of diagnostics. The most important take-away here, is that general diagnostics are diagnostics that have no other spectrum in which they fit, or the problem is unknown. This means that any vehicle left outside of a repair facility with the keys and an authorization to perform diagnosis will be diagnosed under the general diagnosis spectrum.

When the Check Engine Light comes on, you may experience engine performance issues such as poor acceleration, rough idling, or an engine that won't start. In some cases, no abnormal symptoms will be experienced. Other systems like the transmission or ABS can cause the Check Engine Light to illuminate and lights for those systems can come on at the same time. Similar lights may say "Check Engine Soon", "Malfunction Indicator Light" or just "Check". In rare case the engine can overheat.

What steps should I take to diagnose the check engine light on my 2021 Kia K5?

To effectively diagnose the check engine light on your 2021 Kia K5, begin with a thorough visual inspection of your vehicle. Start by checking the gas cap to ensure it is securely tightened, as a loose cap can often trigger the light. Look for any visible signs of wear or damage on engine components, which may provide clues to the underlying issue. After completing your visual check, connect an OBD-II scanner to your car's diagnostic port. This tool will help you retrieve the specific error code that is causing the check engine light to illuminate. Once you have the code, research its meaning through your vehicle's manual or reputable online resources to gain insight into the potential problem. Depending on the error code, you may need to address issues such as a malfunctioning oxygen sensor, a failing catalytic converter, or worn spark plugs. If your initial efforts do not lead to a clear diagnosis or if the problem appears to be complex, it is wise to seek assistance from a professional mechanic or dealership to ensure proper resolution of the issue. By following this structured diagnostic approach, you can effectively identify and address the cause of the check engine light in your Kia K5.

What are the common problems that could cause the check engine light to illuminate in a 2021 Kia K5?

When the check engine light comes on in your 2021 Kia K5, it can be concerning, but understanding the common problems that may cause this warning can empower you to take action. One frequent culprit is a loose gas cap, which can disrupt the fuel system's pressure and is easily fixable by simply tightening or replacing the cap. Another common issue is a faulty oxygen sensor, which monitors the air-fuel mixture and can lead to decreased fuel efficiency if not addressed. Additionally, problems with the catalytic converter, such as blockages or failures, can trigger the light and may require professional attention. Worn-out spark plugs or ignition coils can also cause misfires, leading to the check engine light illuminating. Furthermore, a malfunctioning mass airflow sensor can disrupt engine performance, while issues with the EGR valve can affect emissions. If you encounter the check engine light, consider these potential problems and, if you're comfortable, perform a basic inspection or consult a mechanic to diagnose the issue accurately. Taking prompt action can help maintain your vehicle's performance and prevent more significant repairs down the line.

How urgent is it to address the check engine light in a 2021 Kia K5?

When the check engine light illuminates in your 2021 Kia K5, it is crucial to act swiftly to prevent potential safety risks and costly repairs. This warning signal indicates that there may be an issue with your engine or emissions system, which could range from a minor sensor malfunction to a more serious engine problem. Ignoring this light can lead to further complications, including engine damage or decreased vehicle performance, which can compromise your safety on the road. For DIY enthusiasts, the first step is to use an OBD-II scanner to retrieve diagnostic trouble codes, which can provide insight into the specific issue at hand. Once you have identified the problem, you can research potential fixes or consult repair manuals to guide you through the necessary repairs. Addressing the check engine light promptly not only ensures the longevity of your vehicle but also enhances your driving experience by maintaining optimal performance.

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