2020 Lexus IS 300 Check Engine Light

Certified technicians, only the experts.
Frequently Asked Questions

Frequently Asked Questions

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

  • Confirm whether the light is steady or flashing; a flashing light signals a potential immediate problem.
  • Check the gas cap for a secure fit — a loose or damaged cap is a common and inexpensive cause.
  • Note any drivability symptoms (stalling, rough idle, loss of power) to share with our technicians.
  • Record recent repairs, fuel type used (premium unleaded for the 2020 Lexus IS 300), and warning patterns before visiting the shop.
  • If the vehicle is under warranty, remember warranty-covered repairs must be completed at a certified dealership like Nalley Lexus Roswell.

How long does a check engine light service take?

  • Initial diagnostic scan typically takes 20–45 minutes to read codes and gather freeze-frame data.
  • Minor fixes such as tightening a gas cap or clearing an adaptive code can be completed the same day.
  • Repairs that require parts or deeper diagnosis (ignition coils, oxygen sensors, turbo-related issues) may take several hours to a day.
  • Our factory-trained technicians aim to minimize downtime with streamlined service and quick parts access at Nalley Lexus Roswell.
  • Warranty repairs must be done at a certified dealership to preserve coverage and often save time and cost in the long run.

What is the most common reason for check engine light on a 2020 Lexus IS 300?

  • Faulty oxygen sensors or catalytic inefficiencies that affect emissions and fuel economy are frequent triggers.
  • Ignition misfires from coils or spark plugs can illuminate the light and may lead to catalytic damage if ignored.
  • Loose fuel caps and evaporative emission system leaks are common and typically low-cost to remedy.
  • Turbocharger-related sensors or boost control issues can occur on the 2.0L turbo inline engine and should be diagnosed promptly.
  • Addressing these early at a certified dealership prevents larger repairs and preserves warranty coverage when applicable.

What does it mean when the check engine light comes on in a 2020 Lexus IS 300?

  • It indicates the vehicle’s onboard diagnostics detected a fault — anything from emissions component issues to engine misfires.
  • Codes can range from minor (EVAP leak) to serious (persistent misfire or catalytic converter damage) and require a scan for specifics.
  • A steady light usually signals a non-emergency fault; a flashing light suggests active misfires that can harm the catalytic converter.
  • Timely dealership diagnosis ensures accurate repair, maintains long-term performance, and protects warranty eligibility.
  • Nalley Lexus Roswell provides factory-standard diagnostics and repair documentation that independent shops cannot match for warranty claims.

How much does a check engine light diagnostic cost for a 2020 Lexus IS 300?

  • Basic diagnostic scans at our dealership are competitively priced and often less than independent shops, while delivering higher-level service.
  • Typical scan fees range from a modest diagnostic charge to higher costs if extended testing or road diagnostics are needed.
  • Repair costs vary by failure: sensors and gas caps are low-cost, ignition coils or catalytic repairs are more substantial.
  • Choosing Nalley Lexus Roswell offers immediate savings from accurate diagnosis, and long-term savings from correct repairs done by factory-trained technicians.
  • Remember, any repairs covered under warranty must be performed at a certified dealership to maintain coverage and ensure proper reimbursement.

2020 Lexus IS 300 Check Engine Light Flashing

A flashing check engine light on the 2020 Lexus IS 300 usually indicates active engine misfires that can quickly overheat and damage the catalytic converter. This condition requires immediate attention: continued driving under a flashing light can multiply repair costs and reduce fuel economy. At Nalley Lexus Roswell our technicians will prioritize a swift scan, inspect ignition coils, spark plugs, fuel delivery and turbocharger control systems, and evaluate emissions components. Acting quickly preserves long-term value and often reduces overall expense. If your vehicle is under warranty, repairs must be completed at a certified dealership to keep coverage intact — and our factory-trained team documents repairs for any future claims.

2020 Lexus IS 300 Check Engine Light Reset

Resetting the check engine light on a 2020 Lexus IS 300 is simple technically, but doing so without fixing the root cause can hide problems and lead to larger failures. Our dealership performs a full scan, diagnoses underlying faults, repairs the issue, and then clears codes so you have confidence the problem is resolved. Using Nalley Lexus Roswell rather than an independent shop provides immediate savings through precise diagnostics and long-term savings by preventing repeat repairs. In addition, warranty-covered fixes must be performed at a certified dealership to remain valid; factory-trained technicians use OEM procedures and parts to protect performance, safety and resale value for your Lexus.

2020 Lexus IS 300 Check Engine Light Codes

Common check engine codes for the 2020 Lexus IS 300 include P0420 (catalyst efficiency), P0300–P0304 (misfires), P0171/P0174 (fuel trim lean), and P0130–P0167 (oxygen sensor circuits). Ignoring P030x misfires can damage the catalytic converter, often turning a moderate repair into a costly replacement. Untreated P0420 warnings signal catalytic inefficiency that lowers fuel economy and risks emissions failures at inspection. Fuel-trim or oxygen sensor codes may indicate leaks or sensor failure that affect performance. Repair costs vary—sensor replacements are moderate, misfire diagnosis can require parts and labor, and converter replacement is the most expensive—so prompt dealership diagnosis at Nalley Lexus Roswell typically saves money and safeguards warranty coverage.

Quick Links

Service by Make