Frequently Asked Questions

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

• Confirm the gas cap is tight—an unsecured cap is a common, simple cause for the light.
• Check fuel level and recent fill-ups for contaminated fuel or low octane; this model requires premium unleaded.
• Listen for rough idling or misfires; note any new noises or smells to tell the technician.
• Record recent service or fuel changes and whether the light is steady or flashing—this helps diagnosis.
• If covered under warranty, remember repairs must be done at a certified dealership to preserve coverage.

How long does a check engine light service take?

• Most diagnostics are completed within 30–90 minutes depending on the issue and testing needed.
• Simple fixes like tightening a gas cap or replacing a sensor may be same-day services.
• Complex repairs—ignition coils, catalytic work, or intermittent electrical faults—can require extended testing and parts, taking several days.
• At Nalley Lexus Roswell we use factory-trained technicians and OEM tools to speed accurate repairs and avoid repeat visits.
• Warranty-covered work must be performed here to ensure immediate and long-term savings and to protect your coverage.

What does it mean when the check engine light comes on in a 2023 Lexus RC 350?

• It indicates the vehicle’s onboard computer detected a performance or emissions-related issue—ranging from loose fuel caps to engine misfire.
• A steady light often means a non-emergency emissions fault; a flashing light usually signals a severe misfire risking catalytic converter damage.
• Common causes include oxygen sensor faults, evaporative system leaks, ignition misfires, or catalytic inefficiency.
• Prompt dealer diagnosis protects drivability, fuel economy, and long-term repair costs; many covered repairs must be done at a certified dealer.

How much does a check engine light diagnostic cost for a 2023 Lexus RC 350?

• Diagnostic fees typically range from about $80 to $199 depending on test depth; Nalley Lexus Roswell often offers service specials—see our service page for current offers.
• We frequently cost less than independent shops when you factor in accurate diagnosis, genuine parts, and fewer repeat repairs.
• Immediate savings come from precise troubleshooting and OEM parts; long-term savings come from preserved warranty coverage and avoided collateral damage.
• Any warranty-covered repairs must be completed at a certified dealership to maintain benefits and ensure proper documentation.

What is the most common reason for check engine light on a 2023 Lexus RC 350?

• Loose or faulty gas caps and evaporative system leaks are frequent, inexpensive causes that trigger codes.
• Oxygen sensors and catalytic converter efficiency issues are common—left unaddressed they reduce fuel economy and can lead to costly repairs.
• Spark plugs, ignition coils, and misfire-related faults show up in higher-mileage or performance-driven use.
• Dealer diagnosis ensures correct part replacement and keeps warranty protection intact, often lowering total ownership cost versus repeat independent repairs.