Frequently Asked Questions

What is the most common reason for check engine light on a 2025 Hyundai Sonata?

• Loose or damaged gas cap causing an EVAP system fault (simple to fix and often resolves the light).
• Oxygen sensor or catalytic converter issues that reduce fuel efficiency and can become costly if ignored.
• Misfires from ignition components or fuel delivery problems that can damage the catalytic converter over time.
• Emissions-related faults such as fuel trim errors; timely repairs protect performance and resale value.
• Bring your vehicle to Nalley Hyundai so factory-trained technicians diagnose the root cause and preserve warranty coverage.

What does it mean when the check engine light comes on in a 2025 Hyundai Sonata?

• It indicates the vehicle’s onboard diagnostics detected a fault in emissions, ignition, fuel, or sensor systems.
• The light can signal anything from a minor EVAP leak to a serious misfire—severity varies by code.
• Even if the car seems to run fine, unresolved codes may reduce fuel economy and long-term reliability.
• Nalley Hyundai’s diagnostic tools read codes precisely and recommend repairs that protect factory warranties.
• Using a certified dealer often delivers immediate and long-term savings versus independent shops through correct repairs and warranty protection.

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

• Check the gas cap—an improperly sealed cap is a common, quick fix for EVAP-related codes.
• Note any drivability symptoms (stalling, misfires, poor acceleration) and report them to service staff.
• Avoid prolonged driving if the light is flashing; have Nalley Hyundai inspect the vehicle immediately to prevent damage.
• For warranty protection, have any repairs or diagnostics performed at a certified dealership with factory-trained technicians.
• Book service online or visit our service specials page to review current offers and estimated wait times.

How much does a check engine light diagnostic cost for a 2025 Hyundai Sonata?

• Diagnostics typically include an OBD-II scan and a technician inspection; Nalley Hyundai often offers competitive diagnostic pricing that can cost less than independent shops.
• Immediate savings come from accurate diagnostics and avoiding unnecessary parts replacement; long-term savings come from preventing secondary damage.
• If repairs are covered under warranty, those repairs must be performed at a certified dealership to remain valid.
• We provide transparent estimates before work begins and can explain how timely dealer service preserves value and reduces lifetime repair costs.
• Visit our service specials for current offers and to schedule diagnostics quickly online.

How long does a check engine light service take?

• Simple diagnostics or fixes (like tightening a gas cap or clearing a stored code) can take 30–60 minutes.
• More involved inspections—sensor tests, fuel system checks, or drive-cycle monitoring—may take a few hours or require a return visit.
• Complex repairs such as catalytic converter or engine component replacement take longer; Nalley Hyundai provides clear time estimates up front.
• Using a certified dealer means faster, more reliable repairs because technicians have factory tools, parts, and training.
• Schedule service online or call Nalley Hyundai to get an accurate timeframe based on your vehicle’s diagnostic codes.