Frequently Asked Questions

What is the most common reason for check engine light on a 2025 Toyota GR Corolla?

• Loose or faulty gas cap is one of the simplest and most frequent causes — it triggers an EVAP system code.
• Oxygen sensor or catalytic converter issues can follow if problems go unaddressed, impacting emissions and fuel economy.
• Ignition misfires (spark plugs, coils) are common on high-performance turbo engines and should be corrected quickly.
• Turbo boost or boost-pressure related faults may appear on a 3-cylinder turbocharged engine; early diagnostics prevent larger failures.
• At Nalley Toyota of Roswell we diagnose the root cause with OEM tools, and repairs covered by warranty must be completed at a certified dealership.

What does it mean when the check engine light comes on in a 2025 Toyota GR Corolla?

• It signals the vehicle’s onboard diagnostics detected an issue — from minor EVAP leaks to serious engine misfires.
• Codes are prioritized: pending, active, or flashing (most urgent). A scan reveals the fault codes and freeze-frame data.
• Some faults are emissions-related and affect fuel economy; others can cause engine damage if ignored, especially in turbocharged engines.
• Our factory-trained technicians interpret codes and recommend repairs that deliver immediate and long-term savings, often costing less than independent shops while offering higher service standards.

How much does a check engine light diagnostic cost for a 2025 Toyota GR Corolla?

• Diagnostics typically begin with a computerized scan and inspection; we provide clear pricing up front and explain next steps.
• Nalley Toyota of Roswell often costs less than independent shops due to efficient OEM procedures, genuine parts, and warranty coverage that prevents repeat visits.
• Immediate savings come from accurate diagnosis preventing unnecessary parts replacement; long-term savings come from OEM repairs and preserving vehicle value and warranty protection.
• Remember: any repairs covered under warranty must be performed at a certified dealership to preserve coverage and ensure proper repair records.

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

• Check the gas cap: a loose or damaged cap is an easy fix and a common cause of EVAP system codes.
• Look for obvious signs: unusual noises, loss of power, or smoke — note those for the technician.
• If the light is flashing, stop driving and arrange immediate service — flashing indicates a severe misfire or condition that can damage the catalytic converter.
• Bring your 2025 Toyota GR Corolla to Nalley Toyota of Roswell for a full scan; factory-trained techs and OEM tools ensure accurate diagnosis and warranty-compliant repairs.

How long does a check engine light service take?

• Simple scans and codes review can take 30–60 minutes; many issues are identified quickly with our OEM diagnostic systems.
• Repair time depends on the fault: a gas cap or sensor swap is often same-day; complex engine or turbo issues may take longer and require parts ordering.
• We prioritize clear timelines and upfront estimates; using a certified dealership often reduces overall downtime through proper diagnosis and OEM parts availability.
• Warranty-covered repairs must be completed at a certified dealership to preserve coverage and ensure long-term reliability.