OzoneSal

Hello I am on sure if you found a resolution to your problem but I have the same model RX450HA 2011 and I've on the for several months and have had nothing but problems with the audio system navigation As well as backup camera The code is the same B15D0 and I have retrieved it and reset it through a procedure of turning the headlight yoke knob on and off 3 times as you press the menu button near the touch cursor. This will put you in an informative diagnostics. I've tore down the interior upon a past water problem from dammed up rear clam shell tailgate trim plastic collecting pine needles and depositing water in battery tray which then would roll foward to rear seat 2nd row foot well. Luckily no issues with hybrid Cleaning and Reconnecting any suspect connections from front to back. It can work for several days or not work for several days regardless of freezing or extreme heat. Unsure if a new radio or amp will resolve or if it really is an intermittently bad speaker. I don't know of any fiber optics all connectors I've located were standard wiring. Good luck if this helps you more than me. Keep me in the loop if you resolved yours. 🍻 Cheers from OzoneSal

same problem here 2011 rx450