outside temperature reading way off

[TWI]

I have 11k miles on my '07 Prius. The outside temperature reading is usually about what the radio weather reports and I otherwise observe. After sitting for a week while I was out of town, I took it for a drive today. The reading was initially 66 F, which I thought was low, but OK. The air temperature was in the mid-80's, yet after sitting parked outside for over an hour, the outside temperature reading barely rose to 72 F while driving back home.

I checked the air filter and intake; no signs of a problem there. What might have caused this?

[Sufferin' Prius Envy]

If the sensor gets wet, it will register low for quite some time.

Did you wash the car? Were the roads wet and the car get splashed near the front?

This happens to me most times I wash my Prius.

[TWI]

Good suggestion, but it was dry. The car had been in the garage and the roads were dry when I went out.


New question: Where is the sensor for the outside air?

[Bill Merchant]

The outside air temperature sensor is behind the front bumper in front of the passenger.

[Patrick Wong]

Originally Posted by TWI

New question: Where is the sensor for the outside air?

If you remove the black plastic cover that runs along the front of the engine compartment above the radiator, you should be able to see the sensor.

[TWI]

It seems to be working today: Almost as irritating as when it suddenly didn't!

I'll take a look at the sensor, see if anything looks funny. Thanks for the info.

[avusblue]

We had 95 degree weather in the Twin Cities over the past two days, yet my Prius MFD external temp readout indicated 72 degrees, gradually warming up to indicate 85 on my half hour drive home. All the banks and similar roadside display thermometers were indicating 95 or higher. The car and roads were completely dry.

What gives? My Prius is less than a month old and it seems weird that the readout of outside temperature, on such a computerized car, would be so inaccurate.

Cheers,

Dave

[EZW1]

I had one in my Mazda 5 (which I traded for my '09 Pri) do the exact same thing a couple times. Worst yet, that sensor was tied into the auto climate control so when it read low, it would not cool the cabin. Turns out the dealer could not replicate.

[Patrick Wong]

Originally Posted by avusblue

... My Prius is less than a month old and it seems weird that the readout of outside temperature, on such a computerized car, would be so inaccurate.

Hi Dave,

If you look through the radiator grille you should be able to see the external temperature sensor mounted to a support near the center. See if there's any debris covering the sensor.

[yardman 49]

Originally Posted by avusblue

We had 95 degree weather in the Twin Cities over the past two days, yet my Prius MFD external temp readout indicated 72 degrees, gradually warming up to indicate 85 on my half hour drive home. All the banks and similar roadside display thermometers were indicating 95 or higher. The car and roads were completely dry.

What gives? My Prius is less than a month old and it seems weird that the readout of outside temperature, on such a computerized car, would be so inaccurate.

Cheers,

Dave

I don't know what's stranger: the sensor not reading properly, or 95 degrees in St. Paul.

How about today? The Weather Channel shows that it's 65 degrees up there right now. Did you get a readout from the Prius today, and was it still off?

I also have a Chevy minivan. The outside thermometer, although close to being accurate, is VERY slow to respond. The van must use some heavily averaged readbacks. So when I first start the van, sometimes the temperature will seem to read back to what it did the last time that I first turned it off. So, if I drove it at night, and it was 65, but then I start the car the next day when it is 95, it may start off reading way low, and then after 5 or 10 minutes of driving, slowly start to make its way up to the real temperature.

Maybe the Prius does the same thing?