Outside Temperature Gauge doesn't change

Ok, I have less than 1,000 miles on my 2010 Prius and the outside temperature gauge does not display accurate temperature. I do not have any option packages on my Prius other than SAT radio with JBL audio.

I noticed about 5 days ago the outside temperature seemed to be indicating lower than a time/temp bank display that seems fairly accurate. I thought that it was just an quirk at the time.

Now the Prius temperature displays almost a constant 48 degrees F. And the outside temp. today is near 56 degrees F.

The Toyota service rep in my Pennsylvania area said that the sensor is in the front bumper.

I would not like to have the dash removed to service this problem.


Does anyone else have this problem?

Mine did not change for about 3 hours after I had my car washed. The actual temperature outside was in the high 90s and the gauge read 48. Once the sensor dried out, the temperature returned to normal. Have you been driving in a lot of rain?

Thanks for the response. When I think back to the three instances that I have noticed this 48 degree gauge reading in each case I did have the car washed at the dealership or hand washed by myself and this latest incident it was raining here in Pennsylvania for at least 3-4 days and I had the car parked outsied. Hmmmmmm.

I read an old Gen II thread on Priuschat and they mentioned a similar problem.

Anybody know where the temp sensor is located on the '10?

I have been getting false readings on my outside temperature sensor. I have my grill blocked 100 %. Has anyone else had this problem? Can anyone confirm that the temerature sensor is behind the front bumper on the passanger side (North America) of the car? If so I may remove a portion of the grill block on the upper part of the grill, but I want to remove a piece that is close to the outside temp sensor. Thanks.

Actually it is on the driver's side just behind the lower grill opening. There is lots of wire on it and could be relocated behind the upper grill opening if one chooses. I plan on doing that myself.

On a related note. My wife claims that she has never seen the outside temperature readout greater than 99 F. She is wondering if it can indicate a temperature equal to or greater than 100 F. Has anyone seen it?

My 2009 Prius has shown 104. So has my 1963 wife.

Ditto - except for the second sentence.

Since we are in the Gen3 forum, yes, the OAT displays 3 digits. At lunch time today it displayed 100F. I don't know how high it can go but I know I can look forward to sucky FE.

My GenIII temperature gauge usually is within a degree of billboard temperature displays you see along the road, but like the post from 2009, I thought I broke my gauge after a car wash. The temperature read 88 for about an hour. 88 to me says all of the elements are stuck. I was relieved when it finally started to change. Three hours sounds believable for the external temperature gauge to start reading correctly after getting soaked with water.

I've seen it at 111 but thanks to spiderman for the exact location of the sensor. I knew where it was on my old car and it needs to be cleaned off periodically or it will give false reads. I imagine down at the bumper level, road splash could affect its accuracy.
I should go check it and wipe it off.

Living in Dallas I see over 100F all the time - highest this year I have seen on the display is 108F

See attached for sensor location and temperature range. The sensor is #5 in the diagram.

View attachment 24961

View attachment 24962

I had the same issue on my prius but I ended up getting tired of trying to get it to work right and just replaced it with one from this site: outside thermometer gauge. The gauge is kind of big and clunky but at least it gives decent reads. One of my other buddies on the forum had a similar issue with the gage not working and ended up just getting a new one off a prius at a pick-a-part lot.

I had one single episode (that I did notice) of a wrong external temperature reading.

It was this past summer - really hot and humid outside (34C) and the car was since 8 hrs in the office garage - cooler and drier (22C maybe).
I drive out and after 25 mins the temperature gauge was stuck at 22C. I got worried, but after a good 35 mins it started slowly to move again to 23C. I also thought about humidity build up back then, but thought that 30mins to dry up was a bit too much.

I had it checked from my dealer and he could not find any issue.

Nothing similar happened again - though honestly speaking I am checking the outside temperature not that often. There is another thread about this here.

I just read this thread and now assume that my temperature gauge is working as poorly as the rest of them. I took the car out of a 68 degree garage and it took over an hour driving in 90+ degree air before the temperature gauge show a reasonable temperature. I believe that the problem could be related to condensation on the sensor.

I live in the desert Southwest. Never noticed a problem with the temp sensor. In fact, I was sometimes amused that it seemed quite accurate.

- one more hint that the problem previously noted may be due to moisture.