You already know it's a bad panel/module. The dealer won't be able to elaborate.

Fuses won't cause too-high voltage. They cause NO voltage. Actually, they don't cause it, they're the indicator of too many amps. Use a meter to actually read the voltage at the battery terminals, with and without the engine running. It's possible the bad battery has hurt the alternator.

 

The voltage gauge has returned to normal after installing the new battery.

Are there any repairs I can do for a bad panel/module myself?

 

Unfortunately the technology used in the gauge cluster has evolved far from simple wires and needles that read variable-resistance sending units. It all lives & dies by the data bus and all information is passed on it.

On top of that, even if you knew for sure the cluster was dead you couldn't just grab one from ebay and slap it in. The service manual stresses that only a service replacement part (brand new) should be used because it "learns" everything about the vehicle the first time it's used and could cause damage or be damaged if it's ever put into anything else after that.

 

Yep, check the voltage at the battery first. If voltage is good at the battery then you may have a problem in the instr. panel. The bus error code is telling there is a communication problem between the inst. panel and the pcm.