Frequently Asked Questions

What does it mean when the check engine light comes on in a 2018 Hyundai Sonata Plug-in Hybrid?

• It indicates the vehicle's onboard diagnostics have detected an issue — anything from a loose gas cap to an emissions or battery management fault specific to the 2018 Hyundai Sonata Plug-in Hybrid.
• At Larry H. Miller Hyundai Peoria we diagnose the root cause quickly using OEM-grade scanners and factory-trained technicians to limit down time and avoid unnecessary repairs.
• Our dealership often costs less than independent shops while offering higher-level service; choosing us gives immediate savings (accurate diagnostics, fewer repeat visits) and long-term savings (proper fixes, OEM parts, longer vehicle life).
• Repairs covered under warranty must be performed at a certified dealership to remain valid—our team will explain warranty coverage and next steps.
• You can schedule service online or take advantage of current service specials.
• We also offer service financing so you can get service now and pay later.

How long does a check engine light service take?

• Most diagnostics are completed the same day; a standard engine-light diagnostic appointment typically takes 30–90 minutes depending on the cause for the 2018 Hyundai Sonata Plug-in Hybrid.
• If repairs are required, we provide a transparent estimate and timeline so you can decide—many common fixes are completed within a few hours.
• Because we use OEM parts and factory service procedures, repairs are done right the first time, saving you time and expense down the road.
• Book a convenient time to bring your vehicle in and schedule appointment online.

How much does a check engine light diagnostic cost for a 2018 Hyundai Sonata Plug-in Hybrid?

• Diagnostic fees vary by issue; at Larry H. Miller Hyundai Peoria we price fairly and transparently and often cost less than independent shops while delivering factory-trained techs and OEM parts.
• Paying for an accurate diagnosis helps you avoid unnecessary repairs and preserves long-term value and fuel efficiency for your vehicle.
• We post current offers as service specials, and you can apply service financing to spread payments.
• Schedule a diagnostic online to get an accurate estimate and next steps: schedule service.

What is the most common reason for check engine light on a 2018 Hyundai Sonata Plug-in Hybrid?

• Common causes include emissions sensor faults, catalytic converter/EV system alerts, or battery charging and electrical system issues unique to plug-in hybrids.
• Left untreated, small sensor faults can lead to reduced efficiency, higher repair costs, and potential damage to hybrid components.
• Our certified technicians in Peoria use Hyundai-specific diagnostic tools to isolate causes fast, minimizing cost and maximizing longevity.
• Remember: warranty-covered repairs should be done at a certified dealership to maintain coverage.

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

• Start with basic checks: ensure the vehicle has no obvious leaks, confirm the charging cord and charging status for the plug-in hybrid battery, and check for a loose fuel/cap or visible faults.
• Bring the vehicle to the dealership for a full scan so technicians can read stored codes and give a clear repair plan.
• We recommend scheduling promptly—use our online tool to schedule service and review current service specials before you arrive.
• Service financing is available so you can address issues now and avoid escalating costs later.