[BadmanRick]

Hi bbells - I have a 2017 platinum tundra I purchased in July of 2017. On 8/28/2017 I took the truck and trailer to the Toyota dealership and they installed update t-sb-0231-17. They may have a newer update you will need to check with Toyota. This solved my problems
I purchased an Inovative products of America IPA 9107A Electric Brake Force Meter with Dynamic Load Simulation and Circuit Testing meter. This tests the truck 7pin trailer lights and any break controller. I Hooked it up and tested my break system. It does apply full break voltage during a panic stop and increase voltage as you apply the breaks. I am running my IBC at 9 and it works well. This will not give you the same breaking as The tekonsha p3, but now the factory controller does work.
Do not use electric/hydraulic if you do not have that type break system. Very bad information form dealer.