Hyundai HPS-600 BMS issue

[Mokko]

Hi there!

I have a Hyundai HPS-600 with a 8S 120A BMS that isn't doing what it should be doing, im going to try and give a decent explanation what's going on.

This BMS is not outputting anything at all on P- while there is around 20v on C- and 26v on B-, it cannot be charged thru C- while it does take charge thru P- for some reason, all the cells is within 0.01v.
What i would like to do is to get this BMS to fire back up or replace it with another one but im not sure what type of communication it does via the 4 pin connector that says "VCC" "SD" "SC" "GND, VCC is obviously power, GND is just ground but is "SD" serial data and "SC" serial communication? Could it be RS-485 or CAN communication? That part (the 4-pin) of the BMS sends power and data to the front panel (that has a SMD and SMC pin) while everything else just looks like a "normal" separate port BMS.

I did try to drain the battery fully to see if the BMS would wake up as many other people reports as a working soulution on these but that did not work, i then charged it back up thru P- to get power back into the pack then i also tested to short B- to P- to jumpstart it but as soon as i remove the "short" there is nothing going on again.
If i short B- to P- the front panel fires up and both AC and DC out is functional but it reads 1% battery on the display so the BMS is not communicating, however there is about 24v on both "SD" and "SC".

Does anyone have any idea what to do or know of some other BMS that i could replace this one with?

Best regards from Sweden