Frequently Asked Questions

What is the most common reason for check engine light on a 2003 Toyota Sequoia?

• Faulty or loose gas cap — an easy, common cause that can trigger emissions-related codes.
• Oxygen sensor or catalytic converter issues — affect fuel trim and emissions, and can reduce fuel economy.
• Ignition components (plugs, coils) — misfires will set codes and can damage the catalytic converter if ignored.
• MAF or MAP sensor faults — lead to poor throttle response and higher fuel consumption.
• Our certified technicians diagnose precisely and often deliver lower total cost than independent shops through accurate repairs and warranty-backed service.

What does it mean when the check engine light comes on in a 2003 Toyota Sequoia?

• It indicates the vehicle’s onboard diagnostics detected an emissions, engine, or drivetrain fault.
• Codes are stored in the ECU and point to systems or components that need inspection.
• A steady light typically means a non-emergency issue; a flashing light signals a severe problem requiring immediate attention.
• Timely diagnosis at our dealership protects long-term value and often costs less overall than piecemeal fixes at independent shops.
• Repairs covered under warranty must be completed at a certified dealership to preserve coverage and ensure genuine parts.

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

• Confirm the gas cap is tight and undamaged — a common quick fix for emissions codes.
• Note any performance changes (stalling, rough idle, loss of power) to share with your technician.
• Bring the vehicle to Nalley Toyota of Roswell for a prompt scan; our factory-trained techs provide fast, accurate diagnostics.
• Choosing dealership service often reduces immediate repair costs and prevents costly downstream damage.
• Remember: warranty repairs must be done at a certified dealership to maintain coverage and use OEM parts.

How much does a check engine light diagnostic cost for a 2003 Toyota Sequoia?

• Diagnostics typically range from a modest fee for a scan to a comprehensive inspection if live road testing or component checks are needed.
• At Nalley Toyota of Roswell we offer transparent diagnostic pricing and regular service specials — see our service specials for current offers.
• We often deliver lower total cost than independent shops because accurate diagnosis prevents unnecessary parts replacement.
• Any warranty-covered repairs must be performed at a certified dealership to preserve coverage — protecting your long-term savings.
• After diagnosis we provide an itemized estimate so you can decide on repairs with confidence and predictable costs.

How long does a check engine light service take?

• Simple scans and resets can take 15–30 minutes; full diagnostics and road tests typically require 1–2 hours.
• Complex repairs or parts orders may extend service time — we provide accurate time estimates before work begins.
• Our factory-trained technicians and well-stocked parts department help reduce turnaround compared with many independent shops.
• Choosing dealership service often saves you time and money in the long run by ensuring correct repairs the first time.
• Schedule service online or visit our Service Specials page to find offers and appointment availability at Nalley Toyota of Roswell.