Nav system wonky in 2012 Prius

I don't know if it's the same, but I've had this happen with both my Prius and Garmin Nuvi at times.

The Nuvi did it on I-10 through Houston as recently as spring 2014, but not this spring with new map data. It also did it years ago (2009) on I-95 through New Jersey. I generally have the GPS set to avoid tolls and part of I-10 through Houston includes a left HOV toll lane. At the time, I think the accuracy might have been off enough for the Nuvi to "think" I was on the toll part or something. In New Jersey, I didn't have it set to avoid tolls, but it kept taking me off and back on I-95. For the first few times I had no idea where I needed to exit, so I kept following directions. When we stopped to eat, I did some checking on Google Maps and ended up ignoring further instructions to exit. Once we were off the Turnpike part, it stopped telling me to exit. I haven't been back on that part of I-95 to know if anything has changed with updated map data.

The Prius had no problems through Houston, but has had problems on Hwy 1604 in San Antonio, but that might have been because of some construction that was being done. It also had trouble through El Paso thinking I was either on I-10 or on the frontage road at times. There are times when I think the Prius GPS accuracy is off by several feet, especially when announcing arrivals, but other times it seems accurate to the inch. The Prius had a very difficult time in downtown Savannah last month, but traffic was too heavy for me to tell what was causing it. I'd like to chalk it up to tall buildings, trees and overcast skies affecting accuracy, but I'm not sure I wasn't just turning prematurely.

I'm still not quite used to how the Prius announces turns and Savannah has a lot of turns close together. In heavy traffic, it's not as easy to glance at the map to see how close I am to a turn when the nav tells me to turn. Texas has a lot of turnarounds as part of their underpasses and I've found that the Prius tends to announce those as "sharp" rights/lefts rather than just "turn right/left. Once I got the hang of that, I had an easier time navigating Texas freeways when I had to get off/on for our motels, etc.

I've also had times when the Prius will announce that we've arrived and the destination is still several buildings further. I chalk that up to map inaccuracies, but I suspect it may also be due to periods of GPS inaccuracy. Unfortunately, my Nuvi broke early during our last trip, so I couldn't compare and didn't think to use my Droid Razr. I plan on switching to an iPhone 6 Plus before our next trip in a few weeks and will see how it's nav differs from the Prius. Because so many features are locked out when the Prius is moving, I used the Nuvi to locate restaurants and other POIs along our route and plan to see if the 6+ will work just as well and how much of my data plan it will take, the biggest disadvantage to using a cellphone for navigation.

 

When coming into San Francisco from the Bay Bridge, the nav will suddenly divert from the bridge to Treasure Island. That's because (1) the new span is further north than the old span and (2) the map hasn't been updated to show the new span's alignment. Thus, the nav system puts you on the closest road that corresponds to your actual coordinates.

Regarding the temp gauge, it's displaying air temperature. It doesn't account for what you may actually be feeling in direct sunlight or shade.

 

That's par for the course. I've owned two other Garmin GPS units and they do that too. The Prius tends to do it more often, though. Just be aware of this and do not drive into the bay.

The temp gauge is spot on in my Prius but I'm using a thin layer of epidermis as a comparator. What are you using to compare temperature with?

 

Another possibility is bad map data.

I get it sometimes on my GPS when the map doesn't match the GPS coordinates it's getting from the sky. Get far enough off a road (especially if there are neighboring roads), and the GPS will think you are on a different road and re-route.

 

There is a Toyota Bulletin out for that type of Nav problem. Go to Google and search for T-SB-0051-13. See if that fits your situation and if so, call a dealer for an update. It should be free.

 

There's a thread on the Prius c forum about this TSB, but it applies to all similar models of the nav system:
TSB: Abnormal Entune/Navigation Operation for Display Audio (Non-HDD Type) | PriusChat

 

I went in today and had the Firmware update done for my Nav/Display unit and it fixed the problems I had with the USB not working anymore and the BlueTooth audio not working anymore. A week ago ( all of a sudden ), my USB stick and my BT audio connection just quit with the message "Loading" continuously. The Phonebook, CD player, and maps worked fine.
The service manager said it was part of the T-SB-0051-13 firmware update. He said that it brought the version from 2.0 to 3.2.
Anyway, if things get strange with your Display Audio ( non HDD ) unit, ask for the firmware update.