Outside temperature sensor

<div class='quotetop'>QUOTE(marjam @ Jul 5 2006, 09:27 PM) [snapback]281814[/snapback]</div>

I think I remember others posting that it behind the front grill.

So far, I have only had issues after a car wash, when it seem slow to recover. There was a thread about this a week or so ago.

Other then that it always seems pretty close (it does take a few minutes between updates).

What is your doing?

 

the climate control temp sensor is the one on the dash.

 

yep, just inside the front air dam.

discussed briefly here: http://priuschat.com/index.php?showtopic=21337&hl=

 

I think my temperature sensor is defective and seems to have a lower limit. This morning it was well below 0 outside, but my car said it was 7ºF. In fact, it stayed at 7 for about half an hour before rising. I've seen this before, and have never seen it read anything below 7ºF. Is this a known issue? Does it not get below 7ºF in Japan? :-P

 

<div class='quotetop'>QUOTE(marjam @ Jul 6 2006, 01:20 AM) [snapback]281870[/snapback]</div>

The outside temperature sensor works in Celsius, then converts to Fahrenheit. There are 1.8 Fahrenheit degrees for every Celsius degree, so that is where you get the two degree increments.

Tom

 

<div class='quotetop'>QUOTE(Erik Tkal @ Mar 7 2007, 04:45 AM) [snapback]401058[/snapback]</div>

My bet is the 7ºF is a kind of limitation on the system. It is not defective but a specification.
In Japan, we saw -40ºC (-40ºF).

Ken@Japan

 

My outside temp reading always seems high compared to back clocks -- usually 4 to 6 degrees. I assume it picks up some heat from the car.

 

<div class='quotetop'>QUOTE(eej5 @ Mar 7 2007, 08:30 AM) [snapback]401685[/snapback]</div>

I guesstimate the same difference, and assume for the same reason. The faster I drive into the wind, the closer I suspect the displayed temperature is to the actual outside temperature. Someday, I'll have to actually hand a thermometer out the window.

Dave M.

 

I have noticed the same 2 degree increment. This past winter I saw a -6 for a low, so it must get colder than 7 degrees in Japan. My temp is usually 2 degrees warmer than most other references, no matter what the outside temperature is. I suppose some of it may be the round off error of the 2 degree increments.

Dennis

 

<div class='quotetop'>QUOTE(DWalker @ Mar 7 2007, 07:40 PM) [snapback]401911[/snapback]</div>

In Canada where we have Celsius, I find the outside temperature displayed is usually one degree C warmer than it really is out there. So your two degrees F difference may be partly due to the conversion, but also part of it is because it isn't all that accurate. All you have to do is make a mental correction.
It seems however to get increasing inaccurate as the temperature drops. We had -24C this morning (-11F) and my display was showing -21C all the way to work. Also something that I want to check: 200 yards after I leave my heated condo's underground garage there is a traffic light. This morning, for example, the temperature on the display began plummeting as soon as I got out of the garage (naturally), dropping about one degree every couple of seconds. But as soon as I stopped for the light the temperature hung there without any change. Then when the light turned green and I began moving again, it continued on its plummet. I've noticed this a number of times. I was wondering if it doesn't monitor the outside temperature when it's stopped. On the other hand it could be the engine heat was holding it constant. I need to check that on a windy day.
This conversion of C to F is only one of the bizarre designs in the Prius - what I call "What was Toyota thinking?" For example, the speedometer in Canada is in kilometers (metric), but the cruise control increments in mph (imperial). So in Canada we have the reverse situation with cruise control: if you flick the cruise control level up or down it increments in mph but still displays in kilometers.

 

What Toyota was thinking was probably that the bullheaded stupid
american adherence to non internationally standard and non-scientific
units didn't count for much, so they do everything in MKS like they
should and then make a token nod toward english units by converting
if needed.
.
The sensor is only a NTC thermistor, and is not necessarily the most
accurate device on the planet. I think mine reads about 2 F [see,
duh] high too. It's plenty good enough for the ECM to make its
determinations about running conditions, and that's what counts.
.
_H*

 

<div class='quotetop'>QUOTE(Erik Tkal @ Mar 6 2007, 02:45 PM) [snapback]401058[/snapback]</div>

Yesterday it was -17 F outside here, and that's what the MFD showed.

 

<div class='quotetop'>QUOTE(Tideland Prius @ Mar 7 2007, 08:11 PM) [snapback]402065[/snapback]</div>

Folks, I may sound anal here, but the sensor itself is just a thermocouple and does not know anything about Celsius or Fahrenheit. Now it is possible that the software programmers were lazy and took the signal from the thermocouple and converted it into a celsius value first - then for purposes of displaying fahrenheit, they took that celsius value and converted it to fahrenheit - that could possibly result in a 2 degree jump between readings.

PS: there is nothing inherently superior about celsius versus fahrenheit - its just a different scale - please don't get snooty on us... :blink:

 

whats that other one? Kelvin? isnt my prius talking to me in Kelvin!!! B)

 

<div class='quotetop'>QUOTE(htmlspinnr @ Mar 8 2007, 09:31 AM) [snapback]402257[/snapback]</div>

There is not a chance in H--L that the above statement is true.... With that logic, you have more accuracy with a speedometer reading in KPH rather than MPH

Give me the Quack's name that said that!