2017 Lexus RX450h Has A Check Engine Light

Troubleshooting the Check Engine Light in Your 2017 Lexus RX450h: Common Causes and Solutions

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Reviewed by
Devin Cabugcal
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 2017 Lexus RX450h 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 2017 Lexus RX450h 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 2017 Lexus RX450h?

When faced with a check engine light on your 2017 Lexus RX450h, the first step is to conduct a thorough visual inspection. Start by checking the gas cap; ensure it is securely tightened and free from damage, as a faulty gas cap is a common trigger for the check engine light. Next, pay attention to any additional dashboard indicators or warning lights that may provide further insight into the problem. Utilizing an OBD-II diagnostic scanner is crucial, as it allows you to connect to the vehicle's onboard system and retrieve specific error codes that can direct you to the underlying issue. Additionally, take note of any unusual symptoms your vehicle may be experiencing, such as rough idling or poor acceleration, as these details can be instrumental in diagnosing the problem. By following these initial diagnostic steps, you can effectively gather the necessary information to address the check engine light and potentially resolve the issue without professional assistance.

What are the common problems that could cause the check engine light to illuminate in a 2017 Lexus RX450h?

When the check engine light comes on in a 2017 Lexus RX450h, 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, so ensuring it is secure is a good first step. If the gas cap is not the culprit, consider inspecting the oxygen sensor, as a faulty sensor can lead to poor fuel efficiency and increased emissions. Another common issue is the catalytic converter, which may fail or become inefficient over time, resulting in the check engine light illuminating. Additionally, problems with the mass airflow sensor can disrupt the air-fuel mixture, causing the light to activate. Worn-out spark plugs or a defective ignition coil can also lead to engine misfires, which are often indicated by the check engine light. Lastly, issues with the Exhaust Gas Recirculation (EGR) valve can contribute to the light turning on. Addressing these common problems promptly is crucial to maintaining the vehicle's performance and preventing further damage, making it essential for DIY enthusiasts to be aware of these potential issues.

How urgent is it to address the check engine light in a 2017 Lexus RX450h?

Addressing the check engine light in your 2017 Lexus RX450h is crucial for maintaining the vehicle's performance and safety. Ignoring this warning can lead to serious complications, including engine damage and increased emissions, which may result in costly repairs down the line. The check engine light often indicates underlying issues that, if left unchecked, could escalate into more significant problems, such as reduced fuel efficiency and compromised vehicle safety. While some triggers for the light may be minor and easily fixable, it is essential to have your vehicle inspected by a qualified mechanic to accurately diagnose the issue. By taking prompt action, you not only safeguard your investment but also ensure a smoother and safer driving experience. Therefore, if your check engine light illuminates, it is advisable to investigate the cause without delay to prevent further complications.

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