Error Code B15EC, Pre-Collision Unavailable

Team,

Need some help.

Pre-Collison not avaible. Took the Prius to the dealer (Toyota Lompoc, CA), and they informed me that I had an error (B15EC) that was causing the Pre-Collision not to function. They said the part the error calls out (backup battery/emergency battery) does not exist. They said they could not fix the problem and said I was SOL.

Does anyone have advice, or can provide guidance on this issue? I have an appointment in two weeks with another dealer (Toyota Santa Maria, CA) in a few weeks.

2016 Prius Four Touring
~147,000 miles