Just had the starter changed out on my 91 Ls400. When I start the car everything is fine, when I drive around at low speeds everything is fine. As soon as I hit 30 mph the traction off light and the check engine light come on simultaneously. Has anyone had this issue or know how to fix it?
Thank you

 

You need to pull the codes to find out why the light comes on. Whenever the engine light comes on, the trac off light will also come on.
http://www.lexls.com/tutorials/intro/codereading.html

 

The codes were knock sensor 1 and 2. I did have them replaced when I had the starter done. The person I had do the job didn't do a good job, I had to do a lot of tinkering when I got it back. Is there anything I can do to prevent doing it over again?

 

I suggest you to check the harness connected to knock sensors. The harness uses coaxial shielded cables and the heat tends to degrade them when the car is aged. Just pulling or stressing them often damages the insulation or the connection. The problem is that the harness is not available any more these days. I'd use a Teflon coaxial cable to fix it.