Trailer brake error

Trailer brake error come up on display. 4lo and 4hi, abs, traction control, ! all lighted up. Any ideas whats causing this? 2017 trd

 

First off, do you have a trailer plugged in?

 

I'm having same issue; from what I've read and been told (cousin was a Toyota tech), it's either an axle seal leaking onto ABS sensor, possibly needs an update on software, or something else. But those are the two main things I've been able to find. I've been told the axle seal job is a PITA. Need a press, completely new parts (none of the old parts are re-useable) and needs a press. Mechanic told me probably $800-$1000 ($550 labor/$300+ for parts).

If anyone has any new info to add, would love to hear it.