Does anyone know why the AutoOff function suddently stop working? I changed the oil today, replacing it with Mobil1 Synthetic. Right away I noticed the AutoOff stop working. I drove the car around town all day never once seeing it coming on. I did notice the car is running cooler than usual as result of the new oil, other than that is out of the ordinary. I am thinking the oil is causing the car to run cooler and hence the HAH constantly thinking that it's in the warm-up mode, therefore, AutoOff is bypassed. Does anyone has any input?

That makes very good sense, BUT even on ice cold days, eventually the engine gets up to temp. Hard to think the oil could make THAT large a difference. I have used syn oil in mine and never noticed what yours is doing.

Seeing as you didnt post the yr of your HAH, it does seem like the 12v battery in a couple of 05's have died for one reason or another. Perhaps, if thats low, the engine feels it needs to be running to keep the 12v system charged as a priority?

Be sure to know your radio security code before disconnecting your 12v battery.

Here is where my temp gauge sits when 76 outside

Well...on the way home from work today the AutoOff finally came on, I don't know what the heck is going on for the last two days but I hate the feeling knowing something is wrong with the car. My temp guage is only a tad lower than your Tony, I can only guess of all the possibilites (i.e. friction, temperature, computer need to reset, etc.), what ever, but it's weir.

My battery was full when this weir episo is going, I don't think it's the hybrid battery, but are you referring to the standard 12v battery in the engine compartment? I've a 05 HAH btw.

In the owners manual you can read about certain settings that will block the auto stop from coming on, one of which is when the defroster button is switch on. There are others, but I'm currently on a road trip with our truck and 5th wheel and can't remember them.

SheroBee, Yes, I was referring to the standard 12v battery under the hood. I know mine was weak and the only symptom I had was the Assist wasnt coming on all that often and mpg were about 4 lower than usual.

Here in Florida, 12v batteries dont last that long so I wasnt all that surprised.

GeorgeJ who also replied has some valid thoughts on why the auto stop wasnt working, I know my Prius acted as he suggests yet never noticed this on the HAH yet. We dont use the defog/defrost mode much if ever, but will try it over the weekend on our next road trip.