I own a 1993 Ls 400 with above problems. While driving the trac off light and check engine light come on and the traction system is off. Pushing the traction control button will do nothing and I tested the traction and it is indeed off. I reset the ecu (disconnected the negative battery cable) and problem goes away for 200-400 miles. When I do reset the ecu, the traction and cel are off, and the trac system works perfectly. This was fine in the summer, but now that winter is here, won't be much fun getting out to reset the ecu every 200-400 miles to get traction for these new england winters. Any ideas?

thanks

Mark

 

The problem is not trac it is an engine code when ever a check eng light comes on the trac is disabled must have the car checked out. The reason it takes so long for the code to come back is that most codes are 2 trip detection and it might not happen on 2 consecutive turns of the key.

 

Same problem with my 1991 / LS400. Whenever its get wet and I drive on a rainy day, these two lights comes on and the engine dies. Problem sounds like most other cars when water gets into the electrical system (mostly dstributer caps and plug wires) but my case is different because I just have a recent tuneup and wires change. All these parts in a Lexus are well sealed.

Please advise on a fix.

 

There is a good chance that it is your throttle positioning sensor. I had similar problems, and finally took it to the dealer to check the error codes- and that's what it came back with. I had the sensor replaced, and all is well.

 

This is a 2 years old thread and ***** never respond about his problem.
The check engine or trac light can be anything? Who knows?
My advise is to get your car diagnostic properly or at least find out what the code is..