Frequently Asked Questions

What is the most common reason for check engine light on a 2023 Lexus ES 300h?

• Faulty oxygen sensors or catalytic efficiency codes (P0420) leading to emissions issues.
• Fuel trim or evap leaks (P0171, P0174, P0455) caused by loose gas caps, vacuum lines, or hoses.
• Engine misfires (P0300–P0304) from ignition or fuel delivery faults.
• Sensor failures (oxygen, mass air flow, or temperature sensors) that affect performance and economy.
• Early diagnosis at Nalley Lexus Roswell often prevents larger repairs and provides immediate and long-term savings versus repeated independent shop visits.

What does it mean when the check engine light comes on in a 2023 Lexus ES 300h?

• It signals the vehicle’s onboard diagnostics detected a fault — anything from emissions sensors to engine misfires.
• A steady light usually means a non‑critical issue; a flashing light indicates a severe, active fault that needs immediate attention.
• Many faults affect fuel economy, emissions, or drivability and can escalate if ignored.
• Factory diagnostics at Nalley Lexus Roswell identify root causes and protect warranty coverage; repairs under warranty must be performed at a certified dealership.

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

• Confirm the gas cap is tight and undamaged — a loose cap is a common evap code trigger.
• Look for obvious signs: low oil, overheating, smoke, or major drivability loss — stop driving if severe.
• Note recent fuel quality, fill-ups, or maintenance that might relate to the warning.
• Schedule a diagnostic with Nalley Lexus Roswell for accurate code reading and certified repair recommendations.

How much does a check engine light diagnostic cost for a 2023 Lexus ES 300h?

• Typical dealership diagnostics start with an OBD‑II scan and a hands‑on inspection; estimates vary by issue complexity.
• Minor repairs like gas cap replacement or simple sensor swaps often cost under $300; more complex repairs may be higher.
• Nalley Lexus Roswell often costs less than independent shops when you factor immediate and long‑term savings from accurate OEM diagnosis, fewer repeat visits, and OEM parts.
• Repairs covered under warranty must be performed at a certified dealership to maintain coverage; our factory‑trained technicians will document and perform those repairs correctly.

How long does a check engine light service take?

• Initial scan and inspection typically take 30–60 minutes to identify codes and symptoms.
• Simple repairs (gas cap, sensor swap) can often be completed the same day, usually within 1–3 hours.
• Complex diagnostics or parts-ordered repairs may take a day or longer; Nalley Lexus Roswell provides clear timelines and loaner options when needed.
• Choosing dealership service maximizes efficiency and warranty protection, often reducing overall downtime and cost compared with repeated independent attempts.