P3030 After New HV Sodium Battery

I'm not sure how I'm seeing the battery ECU is going to straighten this out looks like there's a problem with block 2 and 3 and then three and four kind of in the second picture or what have you I mean I would think the battery would just work coming out of the box generally speaking like most of them do and then as soon as it's in the car and you start it up it should run and start to charge and try and balance itself and let the car electronics do their things I mean I've got enough of those battery ECUs to swap and dry but unless something looks bad on it which I can't imagine I guess you're using yours the original one with the car I don't know how the sodium battery ships. The more robust cable shouldn't be an issue I've used junkie black copper colored cables and had fine results cars are still running with them no problem so there's always things like this as long as things are clean electricity can flow everything generally should be pretty happy. Usually the battery ECUs you can quickly see the corrosion and the problems on the plugs and the connectors running from the board to the receptacle by taking the back off cleaning all that up putting it back in service usually they're fine.

 

A P3030 usually points to one or more bad/open module(s) or bad/corroded contacts to module(s). You'll need to remove the bus bar and check modules 1-4, according to Dr. Prius.

 

The module voltages are monitored using the sensing harness ("no. 2 frame wire") and the battery ECU. P3030 is set when a module reading (or more than one) is not just poor, but completely unrealistic (like below 2 volts, or negative).



A realistic-but-poor reading would produce a different code suggesting a possible bad module, but this kind of completely bogus reading is likely to be a problem with the no. 2 frame wire or the voltage sensors inside the battery ECU.

If you've already replaced the no. 2 frame wire (and you inspected that aftermarket one and you're sure it's good and wired right), the battery ECU is a sensible place to look next.

 

@Kashmir ChapmanF is spot on and most likely the problem is with the battery ECU, you can source a Gen2 battery ECU (voltage sensor unit) from eBay, but make sure the seller provide good pictures of the "actual product" and make sure there is no burnt mark nor corrosion.

Best Regards,
Jack