Frequently Asked Questions

What is the first thing to check when the check engine light comes on in a 1990 Toyota Supra?

• Check the gas cap: a loose or damaged cap is a common, easy fix that can trigger the light.
• Note symptoms: listen for rough idle, loss of power, unusual noises, or smells — these clues speed diagnosis.
• Look for obvious issues: low fluid levels, disconnected hoses, or visible wiring damage.
• Avoid repeatedly resetting the light — that can mask problems and risk greater damage.
• If the light persists or the car runs poorly, schedule a diagnostic with Nalley Toyota of Roswell for factory-level testing.

How long does a check engine light service take?

• Diagnostic scan: typically 30–90 minutes using Toyota-grade tools to read codes and live data.
• Minor repairs (sensor replacement, gas cap, hose): often same-day and completed within a few hours.
• Complex repairs (catalytic converter, engine repairs): may require parts ordering and take longer — we provide clear timelines up front.
• Nalley Toyota of Roswell often completes service faster and at lower total cost than many independent shops because our factory-trained technicians diagnose correctly the first time, saving you immediate and long-term expense.
• Repairs covered under warranty must be performed at a certified dealership to preserve coverage.

What does it mean when the check engine light comes on in a 1990 Toyota Supra?

• The light signals an emissions or engine control issue detected by the ECU; severity ranges from minor to urgent.
• Common triggers include oxygen sensor faults, misfires, EVAP system leaks, or catalytic converter problems.
• A flashing light usually indicates a severe misfire or catalytic risk — stop driving and seek immediate inspection.
• Accurate diagnosis requires a scan tool and live-data testing; our technicians use OEM procedures to pinpoint the cause.

What is the most common reason for check engine light on a 1990 Toyota Supra?

• Oxygen sensor faults and aging emission components are frequent causes in older vehicles like the 1990 Toyota Supra.
• EVAP system leaks (including gas cap issues) and ignition misfires are also common and can be simple to fix.
• Left unaddressed, minor faults can lead to poor fuel economy, failed emissions tests, and costly catalytic converter damage.
• Our factory-trained technicians identify root causes quickly, often saving you more over time than independent shops by avoiding repeat repairs.

How much does a check engine light diagnostic cost for a 1990 Toyota Supra?

• Diagnostic fees commonly range from $90 to $150, depending on the depth of testing required.
• If repairs are needed, our dealership may apply diagnostic fees to the repair, reducing your immediate out-of-pocket cost.
• Nalley Toyota of Roswell often costs less than independent shops overall because correct diagnosis and genuine parts reduce repeat visits and long-term expense.
• Any repair covered by warranty must be completed at a certified dealership to maintain coverage and ensure lasting savings.