Outside Temperature Indicator Logic Explained
05-17-2010, 10:45 AM
#1
Thread Starter
Outside Temperature Indicator Logic Explained
I'd thought I'd share some information with you guys. Enjoy!
© 2007 American Honda Motor Co., Inc. – All Rights Reserved 1 of 1
ServiceNews Article
The A/C, the solar blocking glass, and the heater do such a good job keeping the temperature of thepassenger’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 skew the indication.
A07030J
Outside Temperature Indicator Logic Explained
Currently Applies To: ALL Models
© 2007 American Honda Motor Co., Inc. – All Rights Reserved 1 of 1
ServiceNews Article
The A/C, the solar blocking glass, and the heater do such a good job keeping the temperature of thepassenger’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 skew the indication.
A07030J
Outside Temperature Indicator Logic Explained
Currently Applies To: ALL Models
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jeallen (09-30-2019)
02-10-2011, 07:33 AM
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My Outside temperature gage started displaying temperatures that are way colder than reality. I Originally blamed myself for cleaning something till it broke. It was working fine before I deep cleaned the engine bay. I cleaned by hand delicately, no water spraying. Sounds like it may be related to disconnecting my coolant reserve after i filled it with windshield washer fluid? I know I read something in the manual that said that the temp could be adjusted. but seriously this is annoying because I know it is warmer than the thing reads.
My first post as an S2000 Owner.
My first post as an S2000 Owner.
02-10-2011, 09:41 AM
#5
Registered User
yeah my tl has it...and i use the back of my hand against the glass to see if it is cold or hot outside, putting these too variables together gives me an accurate reading: hot or cold or just warm!
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02-10-2011, 12:41 PM
#8
thanks for sharing. so many variables and conditions though for a thermometer. i, too, notice that the readings are usually off. i remember reading in the manual somewhere about adjusting the temperatures if they are really off, but i never really cared to do so.
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