I was driving back from the desert this weekend pulling a small trailer with 2 quads and the SES light came on. All my guages were normal and the truck was running fine. I pulled the code when I got home and it was P0743, Torque converter electrical. I do have a T/C lockup switch installed but have used it many times without this code being tripped? Any ideas on what would cause this code?
Thanks again to all!!

 

That code is fairly common with a T/C lockup. You may have just been lucky not to trip it until now.