2018 Lincoln MKX Has A Check Engine Light

Troubleshooting the Check Engine Light in Your 2018 Lincoln MKX: Common Causes and Solutions

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Reviewed by
Aisha
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 2018 Lincoln MKX 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 2018 Lincoln MKX 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 are the initial diagnostic steps to take for a check engine light on a 2018 Lincoln MKX?

When faced with a check engine light on your 2018 Lincoln MKX, it's essential to adopt a systematic diagnostic approach. Start by visually inspecting the gas cap, as a loose or damaged cap is a common culprit that can easily trigger the warning light. Next, pay attention to your dashboard gauges; any unusual readings may offer additional insights into the underlying issue. If these initial checks do not resolve the problem, using an OBD-II scanner is a crucial next step. This tool connects to your vehicle's onboard diagnostic system, allowing you to retrieve error codes that can help identify the specific malfunction. Additionally, take note of any symptoms your vehicle may be exhibiting, such as rough idling or stalling, as these details can further assist in diagnosing the issue. Finally, consulting your owner's manual can provide valuable information regarding the check engine light and recommended actions. By following this structured approach, you can effectively narrow down the potential causes of the check engine light and take informed steps toward resolving the issue.

What are the common problems that could cause the check engine light to illuminate in a 2018 Lincoln MKX?

When the check engine light comes on in a 2018 Lincoln MKX, it can be a source of concern for any DIY car owner. One of the most straightforward issues to check is the gas cap; a loose or damaged cap can easily trigger the light, and simply tightening or replacing it may resolve the problem. Another common culprit is the oxygen sensor, which, if faulty, can lead to poor fuel efficiency and increased emissions. If you notice a drop in performance, inspecting this sensor could be beneficial. Additionally, issues with the catalytic converter can also cause the check engine light to illuminate, often indicating a more serious problem that may require professional attention. Spark plugs and ignition coils are critical for engine performance, and if they are malfunctioning, they can lead to misfires and trigger the light as well. Lastly, the mass airflow sensor, which plays a vital role in regulating the air-fuel mixture, can also fail, resulting in the check engine light turning on. By understanding these common problems, DIY enthusiasts can take proactive steps to diagnose and address issues with their Lincoln MKX, ensuring optimal performance and efficiency.

How urgent is it to address the check engine light in a 2018 Lincoln MKX?

When the check engine light illuminates in your 2018 Lincoln MKX, it is essential to recognize the urgency of the situation. This warning light is not merely a nuisance; it signifies potential issues within your vehicle's engine or emissions system that could range from minor to severe. Ignoring this alert can lead to more significant problems, including costly repairs and diminished vehicle performance. For DIY enthusiasts, the first step is to conduct a diagnostic test using an OBD-II scanner, which can help identify the specific trouble codes associated with the light. This proactive approach not only aids in pinpointing the issue but also prevents it from escalating into a more serious malfunction. Additionally, addressing the check engine light promptly can enhance your vehicle's fuel efficiency and reduce harmful emissions, contributing to a healthier environment. Regular maintenance and timely repairs are key to ensuring the longevity and reliability of your Lincoln MKX, making it crucial to take the check engine light seriously and act swiftly.

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