Outside temp reading
07-02-2012, 09:29 AM
#1
Instructor
Thread Starter
Outside temp reading
It is taking a long time for the outside temp meter to read correct temperature , when i take it out from garage it should read the right temp within 5-10 mins max but it takes around 20-30 mins to do so
Is this an issue or normal?
Is this an issue or normal?
07-02-2012, 09:35 AM
#2
OP, could be dirty...I never put my trust in those automotive "outside" temp gauges. Seems like they are always a couple of degrees off.
Never trust them to tell you if the road is at freezing.
Never trust them to tell you if the road is at freezing.
07-02-2012, 09:58 AM
#3
The sensor resides behind the front bumper and ask the dealer to take a look at it (if the car is still under warranty). I also know that they can calibrate the sensor to provide more exact readings if they seem off...
07-02-2012, 10:42 AM
#4
Heres something that might help you
CAR CARE TIP: The A/C, the solar blocking glass, and the heater do such a good job keeping the temperature of the passenger’s compartment at a comfortable level that it’s easy to lose track of just how hot or cold it really is outside. An outside temperature indicator in the gauge assembly gives you a reality check.
But keep in mind, this indicator isn’t a laboratory-grade thermometer, and it might not show the same temperature as you’d see on signs or buildings with outside temp displays. The outside air temperature sensor is mounted behind the middle of the front bumper. The gauge control module uses measurements from that sensor to display the outside air temperature. Because of where the sensor is mounted, it may be affected by heat coming off the road, the engine, the radiator, or even the exhaust pipes from other vehicles. To minimize bogus readings, the gauge control module follows a certain logic.
Here’s how that logic works:
When you turn the ignition switch to ON (II). . .
• If the engine coolant temperature is 139°F or lower, the indicator shows the current outside air temperature.
• If the engine coolant temperature is 140°F or higher, the indicator shows the temperature that was stored in memory when you turned the ignition switch to LOCK (0), no matter what the sensor behind the bumper currently measures.
The indicator doesn’t refresh until certain criteria are met:
• If the measured outside air temperature is more than the indicated temperature, the indicated temperature rises 1°F every minute once the vehicle reaches and maintains a speed of 19 mph or faster for at least 30 seconds. As long as the vehicle speed doesn’t drop below that, the indicator refreshes every 60 seconds until the two temperatures match. If the vehicle speed drops below 19 mph, the
indicator doesn’t start to refresh again until the vehicle speed climbs to 19 mph or faster for more than 90 seconds.
• If the measured outside air temperature is less than the indicated temperature, the indicated temperature drops 1°F every 2 seconds until the two temperatures match, no matter what the vehicle speed is.
So here’s the bottom line: The outside temperature indicator seldom delivers readings in real time because of the many heat sources that could throw off that indication. (Acura ServiceNews, March 2007)
CAR CARE TIP: The A/C, the solar blocking glass, and the heater do such a good job keeping the temperature of the passenger’s compartment at a comfortable level that it’s easy to lose track of just how hot or cold it really is outside. An outside temperature indicator in the gauge assembly gives you a reality check.
But keep in mind, this indicator isn’t a laboratory-grade thermometer, and it might not show the same temperature as you’d see on signs or buildings with outside temp displays. The outside air temperature sensor is mounted behind the middle of the front bumper. The gauge control module uses measurements from that sensor to display the outside air temperature. Because of where the sensor is mounted, it may be affected by heat coming off the road, the engine, the radiator, or even the exhaust pipes from other vehicles. To minimize bogus readings, the gauge control module follows a certain logic.
Here’s how that logic works:
When you turn the ignition switch to ON (II). . .
• If the engine coolant temperature is 139°F or lower, the indicator shows the current outside air temperature.
• If the engine coolant temperature is 140°F or higher, the indicator shows the temperature that was stored in memory when you turned the ignition switch to LOCK (0), no matter what the sensor behind the bumper currently measures.
The indicator doesn’t refresh until certain criteria are met:
• If the measured outside air temperature is more than the indicated temperature, the indicated temperature rises 1°F every minute once the vehicle reaches and maintains a speed of 19 mph or faster for at least 30 seconds. As long as the vehicle speed doesn’t drop below that, the indicator refreshes every 60 seconds until the two temperatures match. If the vehicle speed drops below 19 mph, the
indicator doesn’t start to refresh again until the vehicle speed climbs to 19 mph or faster for more than 90 seconds.
• If the measured outside air temperature is less than the indicated temperature, the indicated temperature drops 1°F every 2 seconds until the two temperatures match, no matter what the vehicle speed is.
So here’s the bottom line: The outside temperature indicator seldom delivers readings in real time because of the many heat sources that could throw off that indication. (Acura ServiceNews, March 2007)
The following 3 users liked this post by eazy:
07-02-2012, 12:33 PM
#5
it seems that my Acura outside reading is a few degress above actual so I simply calibrated and set it at -2F and that seems to be giving me a more accurate reading.
My last vehicle it also seemed to read 2 or 3 degrees above the actual air temperature.
mike
My last vehicle it also seemed to read 2 or 3 degrees above the actual air temperature.
mike
07-02-2012, 12:49 PM
#6
^And you did so by...?
07-02-2012, 02:44 PM
#7
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07-02-2012, 03:12 PM
#8
Meh, mine has always been around 8 degrees off. I've known about this since I bought the car brand new, so I just take whatever it says with a grain of salt.
07-02-2012, 08:12 PM
#9
Three Wheelin'
My 09 is dead accurate once it starts to refresh. I anal about stuff like that. I'm the same way with watches. I used a bunch of different calibration methods to get it spot on. I believe it took me several weeks to get it JUST right. I also had to go -2 degrees to get accurate. My home weather station and other two cars all read the same temp when I check them in the backyard before starting.
12-07-2023, 12:03 AM
#11
I know this is an OLD post - but I think I've discovered a wrinkle in the cabin temperature regulation that hasn't been discussed here that I've seen.
Looking on page 21-66 of the '05 RL shop manual, the sensor's resistance-vs-temperature curve goes down as temp goes up, starting at 11k ohms at 14 degrees, dropping to 1k ohms at 104 degrees. The sensor can apparently fail either to the high side or the low side. A very low outside temp reading can be caused by the sensor having too much resistance (like failed open) - where an indicated outside temp much higher than actual would indicate the sensor is partially shorted, with too little resistance. See related post here.
In my case, the outside temp was indicating 131 F and the automatic temp system kept trying to cool the car to compensate. Actual outside temp was down around freezing so there was decreasing heat inside until it blew only cold air. Simply disconnecting the sensor restored cabin heating to near normal, and a new sensor dialed it in the rest of the way.
Looking on page 21-66 of the '05 RL shop manual, the sensor's resistance-vs-temperature curve goes down as temp goes up, starting at 11k ohms at 14 degrees, dropping to 1k ohms at 104 degrees. The sensor can apparently fail either to the high side or the low side. A very low outside temp reading can be caused by the sensor having too much resistance (like failed open) - where an indicated outside temp much higher than actual would indicate the sensor is partially shorted, with too little resistance. See related post here.
In my case, the outside temp was indicating 131 F and the automatic temp system kept trying to cool the car to compensate. Actual outside temp was down around freezing so there was decreasing heat inside until it blew only cold air. Simply disconnecting the sensor restored cabin heating to near normal, and a new sensor dialed it in the rest of the way.
Last edited by rb95gs; 12-07-2023 at 12:15 AM.
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