Actually there are several options. If the ECU is not damaged beyond repair then several companies will repair in the $200-300 range. If it’s beyond repair some sell reconditioned (ECUs that have been unlocked and tested/repaired), that runs about $700. Also, there arecompanies that will unlock a used ECU which would allow a DRBiii or Star tool to program VIN, secret pin, etc. While the chip can be removed most companies connect a reader and clone the data writing it back to a remanufactured one. I believe it’s an eprom chip. I also understand the ECU has diodes which are what gets damaged from reverse polarity. My gut feeling tells me the ECU needs to be repaired. I have a dealer running diagnostics to see what they think it is. Hope to know more tomorrow.