My 2002 toyota prius' HV battery is making a lot of noise, hardly any regeneration watts, and the diagnostic code is P3006, what should a do? Sometimes the car almost stops because the battery shows very low level. Is code P3006 all about the HV battery?

Error Code: P3030
Description: Disconnection between battery and ECU.
The battery ECU monitors a voltage of the battery blocks to detect an open malfunction in internal battery voltage sensor circuits of the battery ECU and the wire harness between each battery block and battery ECU. If a voltage at one of the battery blocks is below a standard level or of all the battery blocks is within a specified range, the battery ECU judges that there is an open in the internal sensor circuit(s) or wire harness. The battery ECU then illuminates the MIL and sets a DTC (Diagnostic Trouble Code).
Trouble Area:
- Junction Block Assembly (Bus Bar Module).
- Frame wire number 2, (Bus Bar and wire harness).
- Battery ECU.

I believe that Code p3030 is an open High Voltage buss. It could be a number of things going on.

toyota prius codes p3022 check engine light on

its a prius. take it in,
lost of things to go wrong with any hybrid, due to huge complexity.
if serious DIY, and feel compelled to get shocked on HV?
then read the FSM buy it ran read all the pages on 3000
and on how not to get shocked and killed. do so , dont guess
study the book.

or go there, first google hit for 3000, read this ?

http://priuschat.com/threads/code-p3000.49355/

could it not just be, that you didnt follow the battery swap instructions
in the FSM then trip these/
reset them and see if they come back.

P3004 - Power Cable Malfunction 130 HV Battery Malfunction. When HV battery voltage becomes lower than inverter voltage
131 Power Cable Malfunction. When main fuse is blown out, service plug is disconnected or limiter resistance is cut off
133 HV Battery Malfunction. When inverter voltage sensor is malfunctioning or limiter resistance value increases

Not much you can do yourself without having diagnostic code information, you'll have to either go to a Toyota dealer or to a shop that has a diagnostic tool that can read code information from the engine computer as well as the hybrid system computers.

YOU EITHER REPLACE HYBRID BATTERY OR HYBRID BATTERY
COMPUTER

P3006 refers to cell 6 in you Hybrid Traction Battery. It will need to be replaced or rebuilt. The batteries don't last forever. Mine died around 109,000 miles. I rebuilt it myself with the help of youtube videos and a module from eBay.

P3006 High voltage power rescorce malfunction

P3025 Battery block 13 becomes weak

i think you have a battery problem