Frequently Asked Questions

What does it mean when the check engine light comes on in a 2021 Toyota Highlander?

• It signals your vehicle’s onboard diagnostics have detected an issue — anything from a loose gas cap to a sensor fault or catalytic converter concern.
• At Larry H. Miller Toyota Peoria, our certified technicians use OEM diagnostic tools to identify the exact code and recommend the most cost-effective repair, often saving you money compared with repeated guesswork.
• Addressing codes promptly protects long-term engine health and fuel economy, and repairs covered under warranty must be completed at a certified dealership to remain valid.
• We offer service financing so you can get the repair now and pay over time; to secure a visit, please schedule service.

How long does a check engine light service take?

• Most diagnostics are completed in under an hour; follow-up repairs vary by issue but we communicate upfront so you know what to expect.
• Larry H. Miller Toyota Peoria prioritizes quick turnarounds with OEM parts and factory-trained techs to minimize downtime for your 2021 Toyota Highlander.
• We offer comfortable waiting areas and loaner options where available; view current offers or savings via our service specials.
• To book efficient care, schedule appointment online and mention any symptoms you’ve observed.

How much does a check engine light diagnostic cost for a 2021 Toyota Highlander?

• Diagnostic pricing can vary, but Larry H. Miller Toyota Peoria often provides competitive diagnostic rates that deliver greater long-term value through accurate OEM repairs and warranty protection.
• Choosing dealership service reduces repeat visits and unexpected costs because we correctly identify root causes the first time.
• Ask our service advisors about financing options and current service specials to make the work affordable now.

What is the most common reason for check engine light on a 2021 Toyota Highlander?

• Common causes include oxygen sensor faults, catalytic converter issues, mass airflow sensor problems, or loose fuel caps — each with distinct symptoms and cost profiles if left unattended.
• Ignoring codes can lead to reduced fuel economy, poor performance, and accelerated component wear; dealership repairs preserve resale value and avoid compounding repairs.
• We diagnose with OEM-grade tools and explain repair options clearly; warranty-covered work must be performed at certified dealerships to keep coverage intact.

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

• Start by ensuring the gas cap is properly tightened — it’s a simple fix that often clears the light after a few drive cycles.
• If the light remains, bring your 2021 Toyota Highlander to Larry H. Miller Toyota Peoria for a full scan so we can interpret codes and recommend lasting solutions.
• Schedule service online to get prompt attention: schedule service. We’ll review estimates, coverage, and financing options before any work begins.

Check Engine Light Flashing

A flashing check engine light on your 2021 Toyota Highlander is an urgent warning that indicates a severe misfire or an event that could damage the catalytic converter. A flashing condition often means unburned fuel is entering the exhaust system and creating heat or stress that can permanently harm emissions equipment. At Larry H. Miller Toyota Peoria in Peoria, AZ, we prioritize immediate diagnostics to limit damage and restore safe operation. Our Toyota-certified technicians use factory-level scan tools to isolate misfire causes — from ignition coils and spark plugs to fuel injectors or engine mechanical issues — and provide transparent estimates that explain immediate and long-term savings of timely intervention. We also highlight available service specials and financing solutions so you can address critical repairs now and pay over time. If your check engine light is flashing, do not delay: schedule service online or contact our service department for same-day guidance and rapid repair.

2021 Toyota Highlander Check Engine Light Reset

Resetting the check engine light on a 2021 Toyota Highlander is straightforward when the underlying issue is resolved, but simply clearing codes without fixes can mask problems and lead to costly failures. At Larry H. Miller Toyota Peoria, we perform a full diagnostic and repair so a reset reflects a true resolution—using OEM parts, calibrated software, and factory procedures. Dealer-performed resets also protect warranties and preserve vehicle history compared with generic resets from independent shops. We document all repairs, explain how we restored system health, and show you preventive steps to prolong engine life and fuel efficiency. Our technicians can reset codes after verifying repairs and running readiness checks; we’ll review potential long-term savings from correct repairs, available discounts, and how service financing can help you manage costs. To ensure a proper reset and lasting reliability, schedule appointment with our service team today.

2021 Toyota Highlander Check Engine Light Codes

Common check engine light codes for the 2021 Toyota Highlander include P0300 (random/multiple misfires), P0420 (catalyst system efficiency), P0171/P0174 (lean condition), and oxygen sensor-related codes. Each carries different risks and potential costs if untreated: misfires (P0300) can harm the catalytic converter and lead to expensive exhaust repairs; unresolved P0420 often means reduced emissions performance and potential failure of state inspections; persistent lean codes can cause poor fuel economy and increased wear. Larry H. Miller Toyota Peoria offers accurate diagnostics that identify the specific fault and a clear cost estimate, often saving customers money by avoiding unnecessary parts replacement. Our certified technicians use OEM parts and follow Toyota procedures to ensure repairs last. We also provide transparent warranty coverage details—repairs under warranty must be performed at a certified dealership—and promote available service specials and financing options. For dependable, efficient service in Peoria, AZ, please schedule service or call our service center for fast diagnostics and repair plans tailored to your Highlander.