Hey guys,

So randomly my traction control just randomly turns on.... Not sure why, it'll be absolutely bone dry out and boom turns on. I'll be driving on the highway and it all of a sudden lights up and starts braking... Any suggestions??
2001 ls430

 

Here is what the owner's manual says about the traction control. Random and unexpected traction control deployment can be dangerous to you driving. I would recommend turn off this function until you resolve the problem.


It sounds like one or both of the rear wheel speed sensors is failing, or the connector is loose. Are you getting any error codes (DTC)?

 

 

Sounds like a sensor problem if it happens at a certain speed everytime. Vehicle speed sensor maybe?

 

I had damaged wiring sub-harnesses on both front wheel speed sensors. It caused a lot of weird things. Sometimes the ABS would turn on and off randomly when coming to a stop during light braking. The Check VSC would pop up then disappear on many occasions without evidence of an error code active in the system. It went on like this for around a year before I got around to fixing it.

You can purchase OBDII scan tools with ABS code reading capability. They cost a bit more than the typical $50-60 dollars units to scan generic OBDII codes. You could buy one of these or take it to Toyota / Lexus to see if there are any stored ABS error codes. Often codes can be stored but don't show any evidence of being active on the display.

It may point you to the right direction. Often electrical problem such as shorted wiring harnesses or damaged connectors can cause intermittent issues like this.