05 toyota prius with many lost comm codes

You need to have that 12 volt battery tested by approved testing equipment and have it passed or failed and replaced usually the communication problems in these cars are because you're 12 volt is not 12 volting now you can test this by putting a multimeter in the DC volts mode on the battery with the engine ready in park just sitting there You're looking for 13 and 1/2 to 14 and 1/2 volts Just sitting there then when you turn the car off nothing on the dash doors closed hatch open test leads on the battery It should fall down to 12 volts but if it's dropping into the 11s down to 10 and lower no good it may work it may allow you to drive the car here and there but no good so you need to make sure that's not happening everybody will say that's not happening and this and that and all that and then after 12 posts they find out they're 12 volts bad so there's always these things that's like the number one cause of communication problems in the Prius other than chewed wires by mice cut by people putting stereos in etc so find what meets the closest of the criteria here and see what's happening. The can bus just doesn't go down for no reason usually it's some kind of a voltage problem or a disconnect whether that disconnect has been chewed wires or human beings connecting things incorrectly adding things whatever it is. And good luck because usually you shouldn't be throwing these cars out for this kind of pretty basic problem