My 2015 Prius had been sitting for several months without being started. The starter battery went flat so when I turned it on, the dash turned on and off in a loop.
I charged the starter battery to full, and tried again. “Hybrid system error, see dealer”. The hybrid system indeed doesn’t run, only the ICE engine runs when I drive it.
There are many ODB-II codes, which I have exported to a file. But the only pending, confirmed, failing test is: P602F(46) ECM “eeprom error”.
I am wondering if it is okay to clear all these codes, since I imagine the low starter battery voltage (and multiple cycles) really confused the electronics.
Could clearing possibly fix the issue, or is that wishful thinking? Should I clear, or take it to the dealer as is?
After I had recharged the starter battery, I exported the codes to a file in case I needed them later. Then I cleared all the codes and restarted the car. Great news, the hybrid system is working perfectly again, and no codes have returned. (I'll update this question again if I regret this down the line!)