I don't know if this has been discussed here but I understand that some folks have issues with the outside temperature readings. I was looking in the Acura shop manual and came across how this sensor works in the TL.

The sensor is mounted on the backside of the front bumper on the driver's side of the license plate. You can look up underneath the bumper and see it sitting there, it's about the size of a salt shaker. This puts it a few inches in front of the radiator and A/C condensor.

According to the manual, the computer reads the temperature at startup if the car has been sitting for a while, else it uses the last stored value. The computer does not read the sensor when the car is sitting still, only when it is in motion above 20mph. Then if the sensed temperature is higher/lower than the displayed value, it increments/decrements the displayed value by one (1) degree and waits 30 seconds to sense again. Once there is no change, or the car's speed drops below 20 mph, the computer starts sensing once a minute.

Hence it is very possible that it may take several minutes for the display to catch up with the actual temperature if you (for example) start your car in a warm garage then move outside to cold weather. Also, the display will not change when you stop moving or drive real slow. This lessens the effect of the radiator on the sensor since the forward motion will blow air over the sensor.

Hope this is informative.