Frequently Asked Questions

How much does a check engine light diagnostic cost for a 1991 Toyota Supra?

• Typical dealer diagnostics range from a basic scan fee to roughly $80–$150 depending on time and complexity.
• At Nalley Toyota of Roswell, we often cost less than independent shops while providing factory-trained technicians and genuine parts.
• Immediate savings come from accurate diagnosis and correct repairs; long-term savings come from avoiding repeat visits and secondary damage.
• Diagnostic fees are frequently applied toward repair costs if you choose to have the work performed at our certified dealership.
• Repairs covered under warranty must be performed at a certified dealership to preserve coverage and ensure quality repairs.

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

• Check the fuel cap: a loose or damaged cap is a common, simple cause; tighten or replace it and monitor the light.
• Look for obvious dashboard alerts or fluid-level warnings that indicate urgency.
• If the light is steady, schedule a diagnostic scan; a scan reveals stored trouble codes and points to the root cause.
• If the light is flashing, stop driving and arrange towing—flashing often signals active misfires that can damage the catalytic converter.
• For warranty protection and accurate repair history, have diagnostics and repairs completed at our certified dealership when applicable.

What does it mean when the check engine light comes on in a 1991 Toyota Supra?

• A steady light indicates an emissions or system fault recorded by the engine control unit; it can range from minor to serious.
• Common causes include faulty sensors, ignition misfires, fuel system issues, or catalytic converter problems.
• We recommend a prompt diagnostic scan to identify the code(s) and prioritize repairs to prevent escalation.
• Handling the issue early at our dealership reduces long-term repair costs and preserves vehicle reliability.
• Remember: warranty-covered repairs must be completed at a certified dealership to maintain coverage and proper documentation.

What is the most common reason for check engine light on a 1991 Toyota Supra?

• Worn or failing oxygen (O2) sensors and loose gas caps are among the most frequent causes.
• Other common culprits include ignition misfires, faulty mass airflow sensors, and emissions control issues.
• If left unaddressed, small sensor faults can lead to poorer fuel economy and more expensive repairs like catalytic converter failure.
• Bringing your Supra to Nalley Toyota of Roswell ensures the correct diagnosis and cost-effective repairs by factory-trained technicians.
• Warranty repairs must be done at a certified dealership to remain valid and to protect your long-term savings.

How long does a check engine light service take?

• Basic diagnostic scans often take 30–60 minutes; a full teardown diagnosis may require several hours depending on symptoms.
• Simple fixes like a loose gas cap or a sensor replacement can be completed the same day.
• More complex repairs—ignition or catalytic systems—may need parts ordering and could take a day or more.
• Our certified technicians streamline diagnosis and repair, delivering immediate savings through accurate repairs and fewer return visits.
• If a repair is warranty-covered, it must be performed at a certified dealership to ensure proper service and continued coverage.