My traction control comes on when driving

It's a Lexus, it knows you need help with traction, so it comes on. Even a few pounds difference in tyre pressure, or a difference in road surface on an incline would be beneficial to have it.

https://www.google.ca/search?q=lexus+gx+460+traction+control+light

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In most cases traction control module in need to receive a signal out of every wheel if four wheel equipped if some reason will not ur engine light would come on need read out using a scan tool to get an idea to lead u to ur issue a sensor a disk a good clean up around the disk hopefully not electrical wiring issue need inspect.
Good Luck

StabiliTrak Indicator Light: If the warning light does not come on then, have it fixed so it will be ready to warn you if there is a problem. If it stays on, or comes on when you are driving, there may be a problem with your StabiliTrak system and your vehicle may need service. When this warning light is on, the system is off and will not limit wheel spin. Adjust your driving accordingly.

This light will also flash when the StabiliTrak system is active. If the StabiliTrak system warning light comes on and stays on for an extended period of time when the system is turned on, your vehicle needs service.

The traction control part of StabiliTrak can be turned off by pressing and releasing the StabiliTrak button if both systems (traction control and StabiliTrak) were previously on. To disable both traction control and StabiliTrak, press and hold the button for five seconds.

Traction control and StabiliTrak can be turned on by pressing and releasing the StabiliTrak button if not automatically shut off for any other reason.

When the TCS or StabiliTrak system is turned off, the StabiliTrak light and the appropriate TCS off or StabiliTrak off message will be displayed on the DIC to warn the driver. Your vehicle will still have brake-traction control when traction control is off, but will not be able to use the engine speed management system.

If the StabiliTrak and/or Traction Control are not operating properly, I encourage you to take your vehicle in for inspection. A certified technician will be able to offer a more accurate diagnosis.

Drive it for a week and it should straighten out.

Very common. Bad wheel speed sensor. Read this
http://ricksfreeautorepairadvice.com/abs-light-on-traction-control-off-gm-products/

ABS light on Traction Control Off GM products Ricks Free Auto Repair Advice

I comes on and off when ever I start the

with traction control set up cars abs and tranction control sensors are in the wheel bearings when a wheel bearing goes out grinding will come from front wheels and will ruin abs and traction control sensors causing the malfunction. Most likely by your description this will be it.

The Enhanced Traction System warning light may come on for the following reasons:

If you turn the system off by shifting to SECOND (2) or FIRST (1), the warning light will come on and stay on. To turn the system back on,shift to THIRD (3) or AUTOMATIC OVERDRIVE

If the traction control system is affected by an engine-related problem, the system will turn off and the warning light will come on.

If the Enhanced Traction System warning lightmcomes on and stays on for an extended period of time when the system is turned on, your vehicle needs service. Adjust your driving accordingly..

2 wheel drive refers to the rear wheels.
The traction control feature applies the brakes to the wheels that are spinning due to lack of traction so that they can slow down and get a grip or traction, if its in 2 wheel drive the system will pulse the brakes and you will hear and feel the system engage usually a buzzing vibration and an indicator light will come on the dash to tell you its engaged

An ABS sensor DOES affect the traction control system. Traction control uses these sensors to determine if a wheel is losing traction. A bad sensor will cause both the ABS and TRACTION lights to come on.
The CHECK ENGINE light however is going to be a seperate problem.