Hi again,
I didnt realize you were talking about the EEPROM inside the microcontroller. Been a while since i worked with one.
Most of them today have at least 128 bytes of EEPROM with at least 10 years retention and 10000 write/read cycles.
Yes some interesting data could be stored there.
But since you mentioned this i gave it a little more thought too. Since the ECU is so limited on this car why not design a secondary ECU, or rather, an ECU with just monitoring capabilities. It could be used to store some different electrical activities such as battery voltage and possibly voltage drop across some of the wires which would provide current level data too for charging and even starting. If it monitored the sensors it could store that too. They make large capacity EEPROMS too these days could store a lot of the measurements on that or possibly interface with a SD card which would give a lot of storage space for data.
Might be a small nightmare to wire up though with all the sensors
Be easy to wire to the battery though.
If i knew the exact OBDII protocol i could replace the entire ECU with a new design which could be a lot better than the original.






