Could someone tell me if the speedometer is read from the front abs sensors or the rear on a gs400. I know I have one bad rear abs sensor or tone ring so the abs and traction control lights are on, but when I reset the traction system using the wire jump method on the diagnostic port under the hood, the speedo will work for about 25 miles and then stops working.

Any ideas of where I should look or is my bad rear abs/tone ring the issue?

I really appreciate your help.

 

Try checking your transmission speed sensors. I think that's what controls the speedometer signal.