The Yellow Triangle Dash Light known as the Master Warning Light (MWL) has come on for me several times for just a split second at very low rpm generally slow moving ahead and when it does the gas pedal loses response for that moment, not a good feeling. .

There is never a screen message since so very quick that the MWL is on then off. The manual notes that there should be a message on the screen?

Had it at the Lexus dealer service dept on 7/31/25 and of course they can't duplicate the MWL, I suppose the usual case for an intermittent issue to move the car on.
Seems to me there should be a code in the computer for this momentary MWL light condition if they search for it..

Going back to Lexus this coming Tuesday 8/5/25 for a recheck and this time will discuss with the Tech or shop manager what gives since this condition needs to be resolved. My 2021 ES 350 still under basic Warranty at 24k mi until 9/4/25

Comments greatly appreciated.

 

Have the battery checked to rule that out as low voltage at startup to ecu can cause multitude of different problems.

 

I’m going on my third week with my car in the shop for an electronics repair. This is also the third time it’s been in for this problem. The Lexus ES dropped in customer satisfaction for technology with the 2024 models. I’m not satisfied either.

 

In late Dec 2024 Lexus put in a new Toyota battery under my Base warranty and checked good this past 3/21/25, will ask for another check with this coming Tuesday trip to Lexus. for the MWL light issue I posted on
Thanks

 

The first time of three that I took my car in for electronics issues they replaced the battery. That helped…..but didn’t eliminate the problem.

 

I had a similar issue and it ended being my alternator. Cost about $2000 Canadian. Which is about $500 USD 🤣🤣

Battery checked ok.

 

Reset the check by unplugging the battery negative for like 5 mins and than plug it back.!!
hopefully that works

 

I have that too on my recent purchase 2021 es 350 blaclline currently 78k km~~ Ran into your issues during traffic jam at highway.

 

When the yellow triangle icon came on was there a message on your screen either on the speedometer area or the main screen? I did not have any message when it happened to me!
Did you notice any loss in gas pedal response? As I noted in OP I lost gas pedal response for a split second all times when the triangle icon came on.

 

When to Lexus yesterday 8/6 to see if this time they could figure out what is going on with the yellow triangle icon coming on. The shop manager drove the car for 15 miles and reported no issues. After his drive we had a lengthy discussion on possible causes but it remains unresolved at this time.