I hope I'm posting in the right place. I recently purchased a L Certified 2020 GX specifically for towing my 16ft Bambi Airstream with a dry weight of 3000lbs. When I went to pick the trailer up for the first time, I was a few miles into my drive home when the Pre-Collision Malfunction warning came up. I was going up a brief incline with no brake controller (I forgot it at home. I use the ECHO Bluetooth brake controller). Took the car to Lexus, they cleared the code. Picked it up again and within a few miles, the code came up again on a straight and flat road, this time with the brake controller. I took the car with the camper straight to Lexus and the cleared the code again; got 28 miles this time before the warning came up again getting off the highway (upward slant and turning right) still with the brake controller. They had the car two weeks and said it is my brake controller even though it went off with and without the brakes. Picked up my camper this last time, again without the brake controller (waiting on the new, wired one they insist I need to come in) and it happened again on a flat, straight road. They have not changed out the sensor or reset the computer even though I requested it. I did have my 7 pin changed in case the connection was bad and have had all of the electrical checked out by an RV shop. I have no idea what else to try. Any suggestions?