Frequently Asked Questions

What is the most common reason for check engine light on a 2018 Lexus RX 350L?

• Faulty oxygen sensor or catalytic converter issues that affect emissions and fuel economy.
• Loose or damaged gas cap creating an EVAP system error — a quick fix but one that should be verified.
• Misfires from ignition coils or spark plugs can trigger codes and reduce performance.
• Mass airflow sensor or fuel system faults that lower efficiency and may lead to costly repairs if ignored.
• Bring your 2018 Lexus RX 350L to Nalley Lexus Roswell so factory-trained technicians can diagnose root causes accurately and protect long-term value.

How long does a check engine light service take?

• Standard diagnostic scans usually take 30–60 minutes to read and interpret fault codes.
• Minor repairs like replacing a gas cap or clearing codes can be completed the same day.
• Complex repairs that require parts or deeper troubleshooting may take a day or more; we provide transparent timelines.
• Choosing Nalley Lexus Roswell delivers faster, more reliable service because our technicians use factory tools and direct parts sourcing.
• Warranty-covered repairs must be completed at a certified dealership to preserve coverage and ensure long-term savings.

What does it mean when the check engine light comes on in a 2018 Lexus RX 350L?

• The light signals that the engine management system has detected a fault that may affect emissions, performance, or safety.
• It can range from minor EVAP leaks to serious misfires that require immediate attention.
• Diagnostics reveal stored trouble codes and live sensor data to pinpoint the issue accurately.
• Prompt dealer diagnosis can prevent collateral damage and avoid higher long-term repair costs.
• We recommend factory-certified service at Nalley Lexus Roswell so warranty work and durable repairs are done correctly.

How much does a check engine light diagnostic cost for a 2018 Lexus RX 350L?

• Diagnostic fees vary, but Nalley Lexus Roswell offers competitive pricing and clear estimates up front.
• Many simple scans and inspections are affordably priced and may be applied to repair costs if you proceed with service.
• Our dealership often costs less than independent shops when factoring in immediate fixes, parts quality, and long-term reliability.
• Using certified technicians reduces the chance of repeat visits and unexpected expenses, delivering greater lifetime savings.
• Remember: repairs covered under warranty must be completed at a certified dealership to maintain coverage and ensure proper parts and labor.

What is the first thing to check when the check engine light comes on?

• Confirm whether the gas cap is loose or damaged — an easy first check that solves many EVAP codes.
• Note any change in performance, smells, or dashboard messages to help technicians prioritize diagnostics.
• Bring your 2018 Lexus RX 350L to Nalley Lexus Roswell for a professional scan rather than attempting resets at home.
• Early dealer diagnosis prevents escalation and often saves money by addressing small problems before they become major repairs.
• If the vehicle is under warranty, have the work done at a certified dealership to preserve coverage and ensure genuine parts and trained service.