Frequently Asked Questions

What is the most common reason for check engine light on a 2023 Toyota GR Corolla?

• Loose or faulty gas cap causing an EVAP system fault — an inexpensive fix that often clears the light.
• Oxygen sensor degradation or failure affecting emissions and fuel economy.
• Spark plug or ignition coil misfires that reduce power and can harm the catalytic converter if left unchecked.
• Catalytic converter or exhaust issues that are more costly if neglected; early diagnosis saves money.
• Bring your vehicle to our dealership so factory-trained technicians can identify the root cause and protect warranty coverage.

What does it mean when the check engine light comes on in a 2023 Toyota GR Corolla?

• It signals the vehicle’s onboard diagnostics have detected a fault in emissions, ignition, fuel, or related systems.
• Codes range from minor (EVAP leaks) to serious (misfires that can damage the catalytic converter).
• Driving without diagnosis can increase repair costs and reduce fuel efficiency.
• At Nalley Toyota of Roswell we perform OBD-II scans, interpret codes, and provide transparent repair estimates.
• Warranty-covered repairs must be performed at a certified dealership to preserve coverage and ensure proper parts and labor.

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

• Check that the gas cap is tight and intact — a simple reseat often resolves EVAP-related lights.
• Listen and feel for obvious drivability issues like rough idle, misfire, or loss of power.
• If the light is steady, schedule a prompt diagnostic; if flashing, stop driving and contact us immediately.
• Our service team will run a full scan and explain immediate and long-term cost implications so you can decide with confidence.
• Remember: warranty-covered repairs must be completed at a certified dealership to remain valid.

How much does a check engine light diagnostic cost for a 2023 Toyota GR Corolla?

• Diagnostic fees vary, but our dealership provides competitive, transparent pricing and occasional service specials — check our Service Specials page for current offers.
• We often cost less than independent shops when you factor in accurate diagnosis, genuine parts, and long-term reliability.
• Correct diagnosis prevents repeat repairs and protects the catalytic converter, saving you money over time.
• If a repair is covered under warranty, it must be performed at a certified dealership; we handle warranty paperwork so you don’t have to.
• Contact Nalley Toyota of Roswell for an upfront estimate and to schedule same-day or next-day diagnostics when available.

How long does a check engine light service take?

• Basic diagnostic scans typically take 30–60 minutes; a full diagnostic with test drives and inspections may take 1–2 hours.
• Simple fixes, like replacing a gas cap or clearing a code after repair, can be completed the same day.
• More involved repairs—spark plugs, sensors, or exhaust components—may require longer, but we provide clear time estimates up front.
• Because we have factory-trained technicians and genuine parts on site, repair turnaround is efficient and reduces repeat visits, delivering immediate and long-term savings.
• Remember that warranty repairs must be done at a certified dealership to preserve coverage and ensure proper completion.