Several weeks back we had some near freezing temps and light rain here in North Texas. The car was parked outside and when I came out from work. The parking lot and the car were wet, not frozen. Got in the car and started it up. Outside temp read 27... which couldn't be right. Stayed there after driving a ways. Got some readings from a Bank and the radio that said it was 33. Figured the gauge was off so I adjusted it up 5 degrees (max adjustment).
Few weeks later - same bank said temp was 78, car read 83. No it looks like I am set too high by 5 degrees. Set it back. Seems it read too low at low temps, or too high at higher temps?
Don't know if the sensor could be bad - or if there is some other adjustment the dealer can do - or do I just live with it?

 

You said you drove "a ways"... it sometimes takes a few minutes to stabilize based on the location of the temp sensor. Assuming you gave it enough time, then you may want to ask the dealer about it next time you're in for service... good luck!

 

Assuming the 4G is similar, the 3G temp guage works off an odd algorthm (IMHO).

First it starts off at whatever temp it was when you last turned the car off. Then, it will incrementally change temperature (1 degree every 30 seconds over 19 MPH or some such thing) as you drive until the measured temp equals the displayed temp.

Further, the probe is calibrated at only one point - 32 degrees. AND the probe is low in the bumper, fairly close to the road. Reason is to be more accurate in cold temps so the driver can anticipate freezing conditions.

Personally, I wouldn't fool with it if it's "in the ball park". Regardless, make sure you've been on the road at steady speed for a bit before making comparisons. Then, if it is consitently off, maybe tweak the adjustment a little.


(I gotta go read the 4G Owners Manual - I don't know if I'm talking out my ass or not. Not sure what crosses over from the 3G. )

 

That's alright, Bearcat, that hasn't stopped others here. To the point of even referring to information in the Owner's Manual which isn't there.

 

In my TSX I can adjust it by holding down the trip reset button while the car was running and it would cycle thru adjusting -3, -2, -1, 0 , 1, 2, 3 degrees F.

 

Maybee the temp reading at the bank is broken!

 

I did drive it a ways - like 15 miles - before I figured it had long enough to 'adjust'.
I also get the fact that when I pull it out of the garage in the morning that it is a different temp outside and it will take a while to adjust.
I agree the bank temp could have been off - although that the temp was right at freezing - yet the car and roads were just wet - not frozen. I knew it had to be around 33 or 34?
Which brings up the other question - what to compare to? That day I knew temp was borderline freezing. But other days (assuming you can't trust the bank) I was wondering what I could use to calibrate to? I don't think holding a thermometer out the window would work - or maybe it would?

 

Damn, can't you let it go! I let you have the last word in the other threads, but that's a unnecessary jab directed to me no doubt, S2000. You got issues cuz, stick to your posts regarding reviews and pictures please. There's not need for posts like that.

 

my car is w/ in my 10 min commute right on. compared to radio, outside therm. at my home.

 

Both of you get over it and move on. I read the other thread and frankly wasn't impressed.

 

Bank thermometer signs are notoriously inaccurate.

 

I'd have to agree with that one. The bank signs tend to be 5 degrees higher than my TL readings, 3G and now 4G. Any static thermometer would be hotter than a mobile one? Where is the T-stat gauge on the TL anyway?

 

From what I've seen on the 2G and 3G TL, the temperature reading starts out too high and then gradually approaches the correct temperature after about 15 minutes. Therefore, I would not give any credence to the temperature reading until the car has been on the road for quite awhile. Also, it is possible for the air temperature to be below freezing and the road to still be above freezing, as the rate of temperature change in the ground is lower than in the air.

 

See page 2:
Outside Temperature Indicator Logic Explained
http://www.in.honda.com/Rjanisis/pubs/SN/B070300.PDF

 

Your ONLY issue to be concerned when things start freezing up and black ice could form:
Roads are wet, and temp drops below freezing...and there might NOT be road salt on the surface. When it gets around 27 degrees F bridges freeze first...the road on regular soil/ground might still be above 32 degrees and not yet frozen.

Just as the wet road freezes, "black ice" can form. Big hint? Tires suddenly sound quiet (they don't kick up road spray). Uh-oh!

Also: it's just snowed, and the temp is JUST BELOW the freezing point. Tire pressure at these temps can thaw ice/snow "underfoot" creating a tiny layer (thin film) of water between the tire and the ice/snow/road surface. this thin film acts as a lubricant...and cars are known to suddenly lose control, or NOT respond to steering/braking commands.

If it's 90 deg F. out there and your thermometer says 98, is that an issue for you? (You might have personal medical issues that are heat related). Otherwise, for the most part, it's ONLY when the roads begin to freeze/thaw when most drivers have to REALLY be careful ... AND... aware.

 

stagnation temp reading?

 

The other problem is is that the sensor (2g and 3g) is in front of the radiator where it absorbs/detects the radiator heat when sitting as well

 

The link to the sensor logic was very helpful. It helps explain why, yesterday in 97 degree heat, the indicator never went above 76 degrees in spite of an hour of stop and go errands. My Avalon doesn't seem to have this problem, though - it reaches temp within 10 minutes in spite of speed or engine temp., it seems.