@Luigarma the easiest and cheapest way to accces all parameters provided by every single ecu of your car would be a mobile phone app called V-Tool in combination with a supported Bluetooth OBD-adapter. This app also allows accessing things like EPB service, service reset, BMS reset and so on via your mobile phone.
You won't get any information of your HV battery, besides the parameters, that are provided by the BECM. Here in germany there are some specialists that offer to calculate the remaining capacity of BEVs traction batteries by monitoring the charging and discharging while driving, but I have no idea if this would work for your car. Simply based on the age of your car, I would expect a drop in the total capacity of your HV battery by 20-30 % depending on the mileage compared to a new battery.
