I had this issue on my 2014 LTD, and yes it was the front passenger sensor. I decided to look for myself what was wrong with the sensor. First I thought it had water in the sensor as it started acting up right after washing the truck(used a power washer). Then I noticed it would beep red intermittently driving slow over bumps.Have a 2014 1794 Edition, 3800 miles. The passenger side parking sensor is going off intermittently - turns the front passenger side indicator on the dash panel red and tone is continuous, as if I am about to collide with the vehicle. Only problem is that the nearest vehicle is about 10-12 feet away. I have
read, on The Tundra Headauarters site, Toyota Issues Tech Tip - 2014 Tundra Pickups Park Assist Issue | Tundra Headquarters Blog that the mounting clips are not real sturdy and allow the sensor to slip.
Toyota has issued a technical tip to dealers about this: T-TT-0287-14.
Has anyone else had this problem besides me?
I took the inner fender apart to get to the sensor, and found the clip barely holding the sensor. I pushed clip back on the sensor, and made sure it was straight. Put it all back together, and took it for a drive.
No issue with it since. It has been functioning as advertised. It beeps with green indicator lines when it picks up an obstruction, and turns to a red line with a constant beep when you are about to touch the obstruction.