Frequently Asked Questions

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

• Inspect the gas cap first: a loose or damaged cap is a common, simple cause and can trigger an emissions fault code.
• Check obvious items: low oil, unusual noises, or signs of overheating before driving far.
• Note recent fueling or maintenance—evap or sensor codes often follow a fill-up or disconnected hose.
• Bring the vehicle to Nalley Toyota of Roswell for a quick scan if the light persists; our dealership often costs less than independent shops and prevents unnecessary repairs.
• Remember: any repairs covered under warranty must be performed at a certified dealership to keep claims valid.

How much does a check engine light diagnostic cost for a 2018 Toyota Prius?

• Typical OBD-II diagnostic scans range locally between about $80 and $150 depending on tests required and live-data analysis.
• At Nalley Toyota of Roswell you get an accurate diagnosis by factory-trained technicians, often at lower net cost than independent shops because we avoid unnecessary parts and identify root causes quickly.
• Upfront diagnostic fees can save money long-term by preventing costly follow-on damage like catalytic converter failure.
• If a repair is covered under warranty, that work must be performed by a certified dealership to preserve coverage and ensure genuine parts are used.

How long does a check engine light service take?

• Simple code reads and verification can take 30–60 minutes, while full diagnostics with road testing and live-data logging often require 1–3 hours.
• More complex issues that need parts or in-depth testing can extend service to a day or more; we provide clear time estimates before work begins.
• Nalley Toyota of Roswell prioritizes accurate diagnosis to avoid repeat visits—this saves you time and money in the long run.
• If a repair is under warranty, having the work done at our certified dealership ensures a timely, covered repair with documented service records.

What does it mean when the check engine light comes on in a 2018 Toyota Prius?

• It signals that a monitored emissions or engine system has reported an anomaly; codes stored in the vehicle describe the subsystem affected.
• Causes range from minor (loose gas cap, sensor glitch) to serious (misfire, catalytic converter efficiency loss) and require proper diagnosis.
• Prompt dealership diagnostics prevent hidden damage—fixing early often keeps repair costs low and preserves fuel economy and emissions performance.
• Repairs that are covered by warranty must be completed at a certified dealership like Nalley Toyota of Roswell to maintain coverage and use OEM parts.

What is the most common reason for check engine light on a 2018 Toyota Prius?

• Common causes include an EVAP system leak (loose gas cap or hose), oxygen sensor faults, misfires, or catalytic converter efficiency codes.
• EVAP and sensor problems are frequently inexpensive to resolve if caught early, while ignored misfires or emissions faults can escalate into expensive converter replacements.
• Nalley Toyota of Roswell identifies the root cause quickly to limit repair costs and avoid unnecessary part replacements—often resulting in lower total expense than independent shops.
• If the issue is covered by warranty, repairs must be done at a certified dealership to keep your coverage intact and ensure genuine OEM parts are used.