Frequently Asked Questions

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

• Check the gas cap for tightness and visible damage — a loose or damaged cap is the most common and simplest cause.
• Inspect battery terminals and visible vacuum hoses for loose connections or cracks that can trigger codes.
• Verify fluid levels and look for obvious leaks beneath the vehicle; low oil or coolant can indicate a serious issue.
• Use an OBD-II scanner to read the stored code; Nalley Toyota of Roswell provides fast, accurate scans so you know the next steps.
• Remember: warranty-covered repairs must be completed at a certified dealership to preserve coverage and long-term savings.

How much does a check engine light diagnostic cost for a 2004 Toyota 4Runner?

• Typical diagnostic fees range from about $80–$150, depending on complexity; Nalley Toyota of Roswell often offers promotions or credits the fee toward needed repairs.
• Repair costs vary widely by code — from a simple gas cap or sensor replacement to more involved repairs like catalytic converter service.
• Choosing our dealership often costs less than independent shops over time due to accurate diagnosis, factory-trained technicians, and genuine Toyota parts.
• Warranty work must be performed at a certified dealership to remain valid; this protects you from unexpected long-term expenses.
• We’ll provide a written estimate and explain immediate and long-term savings from using OEM parts and manufacturer procedures.

How long does a check engine light service take?

• Basic diagnostics can be completed in 30–90 minutes; the initial scan and visual inspection determine the scope of work.
• Minor repairs, such as sensor replacement or gas cap fixes, are often same-day services when parts are available.
• More involved repairs — fuel system, catalytic converter, or engine issues — may require a day or longer for parts and thorough testing.
• Nalley Toyota of Roswell prioritizes accurate diagnosis to avoid repeat visits, delivering immediate savings and avoiding long-term costs from improper fixes.
• If repairs are covered under warranty, work must be done at a certified dealership to maintain coverage and avoid future expenses.

What does it mean when the check engine light comes on in a 2004 Toyota 4Runner?

• The light signals that the vehicle’s onboard diagnostics has detected a fault — ranging from minor emissions issues to engine misfires.
• Common causes include a loose gas cap, oxygen sensor failure, evap system leak, misfires, or catalytic converter inefficiency.
• Severity varies: a steady light often means reduced performance or emissions, while a flashing light indicates an urgent misfire risk.
• Early diagnosis at Nalley Toyota of Roswell can prevent escalated repairs and save money over the life of the vehicle.
• Warranty-covered faults must be repaired at a certified dealership to ensure benefits and long-term protection.