Catalytic converters or oxygen sensors need replacing. Most likely you need to replace your catalytic convertor. That is what happened to me. It is getting too hot which makes your trac turn off to avoid damage.
My engine light is on
The Lexus GX 470 VSC trac light is on because your vehicle is experiencing electrical sensor issues. Take your Lexus to your auto body shop to remedy the problem.
= Service Engine Soon flashing light and Trac Off light on =
It's for better traction in the snow.
I had the same issue so I took it to Lexus for repairs. It seems that light comes on everytime there is a fuel issue rather than a traction issue. You could take it to an Advance Auto and have them pull the code from the computer and it will tell you the problem before you take it to Lexus or your favorite automotive shop. I believe the image they should be using instead of the trac off light is a dollar sign! Last time it went off it cost me 700 dollars.
If your engin light also is on, you need new oxigen sensors!
When the O/D OFF light flashes , that means the powertrain control module has detected a malfunction - get it checked out
Have the ECU scanned with an OBD2 scan tool.
Bring to a shop that has an ABS scanner
Off
Problem with the ABS.
It is informing you that your car is not currently using traction control. It will flash when your car is not getting proper traction from the tires.
The TRAC OFF light is usually caused by a problem in the ABS system. See the link TRAC OFF DESCRIPTION link below for more info.- TechJK -------------