You need to hold down the OK button on the left before powering up the car, I'm sorry did I not say that? Anyway, try it you will get into ET mode. Just keep holding OK after powering up the car for at least 5 seconds, until you see ET in the left screen.
If you reset the MPG number that's just on the outside not the trip meters. You have 3 mpg numbers, the outside one, the one in trip 1 and another in trip 2. Its no worries you reset that one, I reset that often to see my current mpg or mpge numbers, reset trip one before going on a trip, like to Canaan NH this past weekend, and reset trip 2 once a year on January 1st. Trip 2 for me shows 104.01 gallons burned with my Maxie since Jan 1st, that's how I keep track of how much fuel I use per year and my mpg number for the year. My lifetime avarage is 68mpg in 3 years, this year so far I'm at 78mpg but its going to go down, I'm going to Canada on Wednesday so more gas burned and less MPG overall from 78 downwards.
Let me know if you get into ET mode OK.
And just for the record, I will go check my 12v battery now. Last time I checked it its around 12.22 or 12.26v, I made a video of it. That's normal. It can never be at 12.7v unless its just off the charge. Let it sit overnight and I guarantee you it won't be at 12.7v, that's overvoltage a full 12v battery is no higher than 12.6v usually, but there is some load on it in the car so it won't even be that high after a few hours of not charging and the car not being plugged in.
OK just checked it showing 12.52v, higher than last time I checked. My guess is that maybe last time I did this it was during the winter months, not sure. Anyway I did charge my car yesterday at the Big-Y from 4% to 56% but its been sitting since I came back last night. HVB now showing 50%.
By the way, if your battery was down to 3v then it suffered some damage, it may be unable to charge as high just FYI.
Edited by rbort, 22 August 2016 - 09:28 AM.