Hey DIYGuy,
Did you ever get this problem fixed? I have the exact same thing going on, I bought two new sensors (17 and 18) before i found this post. I think i also need a new #15, because of the same symptoms, my car's temp gauge read's all the way hot, even after sitting outside all night in below freezing temps.
Does anyone know the Honda part number or correct name for sender #15?
Thanks!!!!