Frequently Asked Questions

How much does a check engine light diagnostic cost for a 2021 Lexus IS 300?

• Typical diagnostic fees range from $90–$150 for an OBD-II scan; more complex diagnostics may require additional time and testing.
• At Nalley Lexus Roswell we often cost less than independent shops while providing factory-trained technicians and Lexus-specific equipment.
• Immediate savings come from accurate diagnostics that prevent unnecessary part replacement; long-term savings come from preserving engine and emissions components.
• If a repair is covered under warranty, it must be performed at a certified dealership to maintain coverage and ensure OEM parts and proper documentation.

What does it mean when the check engine light comes on in a 2021 Lexus IS 300?

• The light is a sign the engine control unit detected a fault — anything from a loose gas cap to misfires or emissions component failures.
• Common triggers for this turbocharged 2.0L inline-4 include oxygen sensor or catalytic converter issues, misfires, EVAP leaks, or boost control faults.
• Ignoring the light can reduce fuel economy (EPA: 21 city / 31 hwy), increase emissions, and lead to costly damage to the catalytic converter or turbo system.
• Certified service at Nalley Lexus Roswell ensures correct diagnosis, OEM parts, and warranty-compliant repairs that often save you money now and over time.

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

• Start with simple checks: ensure the gas cap is tightened properly — a loose cap is a common and quick fix for the EVAP system.
• Next, monitor performance: note any loss of power, unusual noises, smoke, or a flashing light—those details guide technicians.
• A professional scan with OEM-grade equipment at Nalley Lexus Roswell will pull trouble codes, interpret them for your 2021 Lexus IS 300, and recommend repair priorities.
• Remember: warranty-related repairs must be completed at a certified dealer to keep coverage and receive long-term savings from factory-trained service.

How long does a check engine light service take?

• Basic code reading often takes 20–45 minutes; diagnosing intermittent or complex faults can take several hours or require test drives and component testing.
• Minor repairs like replacing sensors or tightening fittings may be completed the same day; major repairs such as catalytic converter or turbo work require parts and more time.
• Nalley Lexus Roswell schedules service to minimize downtime and often completes diagnostics faster than independents thanks to factory tools and streamlined processes.
• When covered by warranty, repairs must be performed at a certified dealership to secure the warranty benefits and guarantee proper long-term performance.