Last week, in the Boston area, during a very cold morning (~ 5 degrees F.), my 2005 Prius (16K miles) slipped into "B" position all by itself. I assume that this is not supposed to happen and was related to the cold, as it hasn't happened before. I'm about to take it in to a dealer for oil change and recall related to the software update. Any thoughts?
Definitely should not happen. I am in Boston area and we've had temps to 0 deg so far and never happens on my car.
You mean the dash display showed it as being in B? Are you sure you didn't accidentally bump the shifter? That's really easy to do, as all you have to do is pull/push down; you don't have to pull left first as you do for Drive, Neutral or Reverse.
Yes, the trans shifted into "B." I'm quite sure that I didn't just bumb it. This also happened more recently when the temperature was just below freezing.
I'm curious how this situation was resolved. We have a 2007 that is behaving like it is in "B" (slowing down when we release the gas pedal, crappy MPG) yet the dash says it's in "D", and yes, the parking brake is off! We are also able to put it in reverse. We got it a couple months ago with 31K miles on it.
It's supposed to slow down when you release the gas while in "D". Deliberately shift to "B" and compare the two. If there is no difference in behaviour then there is a problem. Boilerplate: Did a 2007 Owner's Manual come with the car? If not then buy one, either online or from a dealer. It's full of info that you need to know. And if you don't have Toyota's Scheduled Maintenance Guide then see here: Toyota Parts and Service
The car will exhibit B-like behavior after the battery gets full on a long steep descent. It sounds, however, like you're experiencing this continually, yes?
I have experienced my 2008 Prius shifting by itself into "B" at least three times on the freeway. I know I put it in "D" when starting out. After an hour (or more) of driving I just plain notice it is driving "different" and look at the dash, and yep, it's in "B". I just pull over in a safe place and restart in "D". Now here is the kicker - recently had an experience with the gear shifter (see posts on gear shifter stuck in Neutral). It was HOT, and gear shifter would revert to neutral from either "D" or "R". It would drive if I held the shifter in "D" or "R". The following morning (81 degrees) it is shifting fine. Experienced folks in the other posts indicate the gear shifter assembly is the culprit. So to the driver who says shifter went to "B" by itself, I believe you. Patrick Wong replied to my question about this and said if the gear shifter is flaky, it is entirely possible for the shifter to go to "B" by itself. My car is being looked at by the dealer on Thursday, I'll post results.