1999 Lexus ES 300. My check engine and trac off light came on at the same time. Even pushing the trac off switch the light remains on. The manual says to take the car to a Lexus dealer. Is this a serious problem ( live in MT far from a dealer)

it means the traction control is off and will not help in a skid, ect...
there must be a problem with one of the sensors/componet that the track and engin computer use to control the track system.
being the engin light is on along with the track light, any parts store can scan the engin computer and tell you the diag. code.
do you live by a autozone, pepboys, advance auto stores?

Was any recent brake work done? Was any recent work done to the tires or rims? Was any recent work to the suspension of the car? You gotta check all this out. In the process a sensor could have been damaged or accidentally disconnected.

sound like a wheel seed sensor has gone bad.
we would need to have the computer code to be for sure. have the computer scanned at a local shop and post the results here for further advice.

Once a wheel sensor goes bad the computer can't accurately calculate vehicle speed and turns he traction control off and the "check engine" light on.

Let me know how it works out or if you need more info.