Frequently Asked Questions

What is the most common reason for check engine light on a 2002 Toyota Corolla?

• Faulty oxygen sensor (O2) or aging catalytic converter are frequent causes that affect fuel economy and emissions.
• Ignition issues such as worn spark plugs or coils can trigger misfire codes and reduce performance.
• Loose or damaged gas caps and EVAP leaks (evaporative emissions) often cause emissions-related codes and are simple to fix.
• Addressing issues at our dealership often costs less than independent shops while delivering factory-trained technicians, genuine parts and warranty protection.
• Repairs covered under warranty must be performed at a certified dealership to maintain coverage and maximize long-term savings.

What does it mean when the check engine light comes on in a 2002 Toyota Corolla?

• It indicates the vehicle’s onboard diagnostics (OBD-II) detected a fault in emissions, engine, or drivetrain systems.
• Codes range from simple items (loose gas cap) to serious faults (misfires) that can harm the catalytic converter if ignored.
• Our dealership uses advanced scanners to identify the exact code and recommend a qualified repair plan with upfront pricing.
• Choosing Nalley Toyota of Roswell often delivers immediate savings via accurate diagnosis and long-term value through genuine parts and warranty-backed repairs.
• Remember: warranty-covered repairs must be completed at a certified dealership to remain eligible for coverage.

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

• Check the gas cap — a loose or damaged cap is a common, inexpensive cause of emissions codes and can reset the monitor after tightening.
• If the light persists, bring your Corolla to our service center for a fast OBD-II scan to read stored trouble codes accurately.
• Our technicians will explain required repairs, estimated costs and potential long-term savings compared to repeated independent fixes.
• Warranty-covered work must be performed at a certified dealership; we provide factory-trained service and genuine parts to protect coverage.

How much does a check engine light diagnostic cost for a 2002 Toyota Corolla?

• Diagnostics typically start with an OBD-II scan; Nalley Toyota of Roswell provides clear diagnostic pricing and service specials—check Service Specials for current offers.
• We often cost less than independent shops when factoring in correct diagnosis, no repeat visits and genuine parts that last longer.
• After diagnosis, we provide a transparent estimate for repairs so you can compare immediate and long-term savings from factory-trained repairs.
• If a repair is covered under warranty, it must be completed at a certified dealership to preserve coverage and maximize value.

How long does a check engine light service take?

• Initial OBD-II diagnostics usually take 30–60 minutes to read codes and perform a basic inspection.
• Repair time varies by issue: simple fixes like gas cap or spark plugs can be completed same-day; complex repairs may require parts and additional time.
• Our service team provides estimated completion times and helps prioritize repairs to minimize downtime and reduce long-term costs.
• Scheduling service with Nalley Toyota of Roswell ensures work is done by factory-trained technicians who protect warranty coverage and vehicle value.