2021 Lexus LX570 Has A Check Engine Light

Troubleshooting the Check Engine Light in Your 2021 Lexus LX570: 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 Lexus LX570 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 Lexus LX570 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 2021 Lexus LX570?

When faced with a check engine light on your 2021 Lexus LX570, the first step is to conduct a visual inspection, starting with the gas cap. Ensure it is securely tightened and free from damage, as a faulty gas cap is a common culprit for triggering the light. Next, utilize an OBD-II scanner to connect to the vehicle's diagnostic port; this tool will help you retrieve specific error codes that can pinpoint the issue. Pay attention to any additional symptoms your vehicle may exhibit, such as unusual noises or performance changes, as these can provide further clues. Additionally, consulting your owner's manual can offer insights into what the check engine light signifies and any recommended troubleshooting steps. If these initial diagnostics do not resolve the issue or if the problem appears complex, seeking assistance from a qualified mechanic is advisable to ensure proper diagnosis and repair. By following these steps, you can effectively address the check engine light and maintain your vehicle's performance.

What are the common problems that could cause the check engine light to illuminate in a 2021 Lexus LX570?

When the check engine light comes on in your 2021 Lexus LX570, it can be concerning, but understanding the common issues 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 and is easily fixable by simply tightening or replacing the cap. Another common issue is a faulty oxygen sensor, which not only affects fuel efficiency but can also lead to more significant engine problems if left unaddressed. Additionally, problems with the catalytic converter can trigger the light, indicating that it may be failing or inefficient, which requires more in-depth diagnostics. Worn-out spark plugs can also be a factor, as they are crucial for proper engine performance and can lead to misfires if not replaced timely. Furthermore, a malfunctioning mass airflow sensor can disrupt the air-fuel mixture, causing the engine to run poorly. Lastly, ignition coil failure can result in rough idling and misfiring, necessitating immediate attention. By being aware of these potential issues, you can take the first steps toward diagnosing the problem, whether that means checking the gas cap or consulting a mechanic for more complex repairs.

How urgent is it to address the check engine light in a 2021 Lexus LX570?

When the check engine light illuminates in your 2021 Lexus LX570, it is crucial to act swiftly to prevent potential complications. This warning signal indicates that there may be an underlying issue with your vehicle's engine or emissions system, which, if ignored, could escalate into more severe problems. By addressing the check engine light promptly, you not only safeguard your engine from further damage but also enhance your vehicle's fuel efficiency and overall performance. While some triggers for the light may stem from minor issues that can be easily fixed, it is essential to conduct a thorough inspection or consult a qualified mechanic to accurately diagnose the problem. Neglecting this warning could lead to costly repairs and safety risks, making it imperative to prioritize the check engine light as a critical aspect of your vehicle's maintenance. Taking immediate action ensures the reliability and longevity of your Lexus LX570, allowing you to enjoy a safer driving experience.

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2021 Lexus LX570 Check Engine Light Guide | RepairPal