Does the Prime itself track how many miles are driven on its ICE versus the electric (EV Only) motor?
Not if you mean EV mode vs HV mode. Prime does display EV driving ratio, but it include EV driving while under HV mode.
the 'black box' tracks everything, but that info is not available. you can use a trip meter as sk shows above,
Ya sorry, I meant total for the life of the vehicle, not just a single drive or since a reset. If I never reset would this be what I’m looking for? And yes HV vs EV. Went to the dealer for my first prepaid service at 5k and they put “No Oil” needed, so I assume that means my EV ratio since the beginning is pretty darn good, and wondered if I could view that somewhere. Maybe that’s common with Prius Primes?
Your Toyota care at 5K does not include oil change. Scheduled oil change is every 10K for PRIME. I am due for 15K maintenance tomorrow. As for the lifetime HV vs EV, the Drive monitor under ODO will show the EV Driving ratio for that ODO reading assuming you did not reset anything. (To tell the truth, I am afraid of resetting anything, so I don't even know how to reset that reading. lol) BUT, as I stated above, the ratio is for traction battery motor driving and ICE driving not for EV mode driving vs HV mode driving.
make sure you record all your numbers on paper, or take pictures. dealers have been known to reset everything during service. also, if they disconnect the 12v for anything, you lose them all.
Yeah they deleted my lifetime MPG record during my 20,000 mile service. Fortunately since my driving style hasn't changed, I'm sure it will trend back to what it was before in time.
is there a way to find out the electric vs gas miles overall for the vehicle? Even if it is by putting something into ODBI II?
As @bisco commented, there is no easy way to track the EV mode and HV mode driven distance automatically. You have to manually reset one of Tripmeter to zero when you start EV and must remember or write it down when EV runs out. If the distance driven is longer than the EV range, then the Drive Monitor on the MID does display the total distance driven. Or if you do not do multiple charges, the daily log also gives you the total distance driven.
If you know your total mileage and your mpg, you can do the math. I believe it gives you credit for 199 mpg on electric. Current mileage divided by 199 gives you percentage on electric the rest is gas.