I hope this works for you. It absolutely did not for me and Toyota will not do anything about it. The backstory - 2006 Tacoma, mildly driven around town, 125k miles. Was undercoat treated around 2010 Due to recall. Rubberized type of treatment.
This past Dec, local shop was doing oil, tire rotate, etc, called me and said I had to come see the frame. Went down and watched tech stick his hand into multiple huge voids that had appeared in the side walls of the frame. The coating was still on the frame, but you could pull big chunks of the rotted frame off, all rusted on inside. Guy that owns the shop said, hey, no charge today, get this home, please don’t drive this.
Wife was beyond pissed. She pulled all the docs she had kept from recall and got on phone with Toyota dealer. This ended up with a manager who said they had inspected & taken pics of frame, all was good, then coated. Said we should take it up with Toyota, and quietly admitted we were likely screwed. Wife calls Toyota, and absolutely ran it up their flagpole as high as she could get - 4 different calls. Questioned every part of their process, even if the frame was fine then what did the coating do to the frame material, sealed in any water, etc, etc. They kept asking her, “you know how many frames we replaced?? We did what we needed to do.”
Long story short, Toyota said truck was 14, we got our use from it, they did their job, we would get no relief. They offered to replace frame, costing us $10k. That went over poorly… We currently have a perfectly good 2006 Tacoma in our driveway that has been taken off the road and we are not sure what to do with it. I had been in process of replacing headlights (originals were hazed) and making other reconditions to it, was one of my covid projects. Fun vehicle, wanted it to be around for at least 300k miles.
Good luck to you, and know Toyota will do anything they can not to remedy future frame rot issues You might encounter.