Lexus Check System Light (Solved)

The check engine light is used as an all-purpose multi-issue warning light to alert the driver to a problem in their vehicle. If you have problems that could cause the check engine light to turn on is a software glitch or update, at least a gas cap, a poorly performing catalytic converter or multiple issues with the tire pressure monitoring system could be the cause of CHECK SYSTEM light.

I Have A Lexus And The Check System Light Just Turned On. What’s Going On?

The Lexus computer system monitors a number of different systems inside the vehicle including the catalytic converter and the performance of each of the cylinders in the engine.

If the check engine light appears on your vehicle’s dashboard, it doesn’t always mean the vehicle will fail and overheat. There are a number of reasons why the check engine light will appear. Some of these issues are easy to fix and others will cause hundreds of dollars. 

Here are the most common reasons why the check engine light will appear on Lexus’s dashboard.

There’s A Problem With The Tire Pressure Monitoring Sensors Or With The Tires

One of the main issues that cause the check system light to appear on the dashboard of a Lexus is issues with the tire pressure.

The Battery That Powers The TPMS Sensor Is Dead

Each of the TPMS sensors has a battery that powers it. These batteries will occasionally die. This is why it is important to replace the sensors every few years. 

When the battery dies, the check system light will appear on the dashboard. You cannot replace the battery without replacing the sensor as well. Replacing the dead battery and its sensor should take less than an hour for a Lexus Certified mechanic.

An Issue With The Tire Pressure Monitoring Sensors

Another part of the tire pressure monitoring system is the TPMS sensors. These are sensors that monitor the tire pressure. There could be an issue with the sensors providing faulty data to the entire monitoring system. The sensors could need replacing.

Replacing the TPMS sensors is routine and should happen every few years. To replace these sensors, the cost of parts and labor can reach up to $150.

A Glitch In The Tire Pressure Monitoring System Caused The Check Engine Light To Appear.

Like any program that uses software, the tire monitoring system in a Lexus can occasionally experience glitches. The cause of the glitches can either be faulty data from the sensor or a bug in the computer system that the engineers and developers did not find. 

Sometimes, the vehicle’s monitoring system will start glitching if there is a new software update that requires downloading. 

Solution: Check the vehicle software system to see if there is a new software update available and download it. Or, you can reset the computer system in your Lexus and it will erase all the previous data. Bad data could cause software glitches so this should clear the problem right up.

The Gas Cap Is Loose.

It could be bad if air gets into the fuel tank. So, many cars are programmed to activate the check engine light if the gas cap is not rotated all the way to the end or if the driver left it off completely after they got gas. Fixing this issue is simple: just place the gas cap on the tank opening.

The Catalytic Converter Is Not Reducing Emissions

In every vehicle, there is a device called a catalytic converter. This device reduces the number of toxins and pollutants that the vehicle produces. If your catalytic converter is not working as it should, your vehicle will not be able to pass the smog test. 

If your Lexus does not pass the smog test, it will not be legal to drive as it produces too many pollutants.

Solution: Clean Or Replace Catalytic Converter

A certified Lexus mechanic can use the onboard diagnostic system in the Lexus and their own diagnostic tools to determine if the catalytic converter is experiencing issues. 

If it is a catalytic converter, there are two options to pursue:

The first option is to have the mechanic remove the catalytic converter and clean it out. The second option is to replace the catalytic converter. 

If possible, it would be better to flush out the catalytic converter than to replace it. Flushing the catalytic converter shouldn’t take more than an hour and cost less than $50. However, purchasing and installing a brand new catalytic converter can cost between $1,000 and $2,500. 

The catalytic converter is an extremely expensive piece of equipment. In fact, there has recently been a rise in the number of catalytic converter thefts all across the United States. 

How To Initialize The TPM System.

Reinitializing the TPM system will negate and erase all faulty data, so the system can operate with new uncorrupted data.

  • Turn on your vehicle.
  • Activate the menu by pressing the on/off button. The word Check System should appear on your dashboard.
  • Scroll through the menu options and find the menu Tire pressure. Then, hold the on/off button for 3 seconds until the word initialized appears on the dashboard.

If the check system text disappears, then your Lexus was experiencing a software glitch. But if the text remains, then there is an actual physical issue with the TPM system.


Issues with the tire pressure or a faulty check system light are all reasons why the check system light will appear on the dashboard of a Lexus. If the catalytic converter is not working correctly, it is in your bank account’s best interest to flush the converter out first rather than replace it first. 

If a mechanic checks the tire pressure and the tires are perfectly fine, then have them reset the check system light and monitoring system. Resetting the system will erase all the data, including faulty data.

  • Eric Williams

    I'm the founder of Daily Car Tips. I wrote articles in the automotive industry for more than 10 years, published in USA and Europe. I love sharing my knowledge and insights with fellow enthusiasts. Join me on this journey as we explore the exciting world of cars together!

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