External Temperature very Inaccurate

The "external air" temperature value displayed on the right side of the "eyebrow" is grossly incorrect, perhaps displaying 69 degrees (F) when it really is 85 ºF.

Is it measuring some other temperature, like cabin temp?

Has there been any resolution to this problem?

It was observed and discussed back in December and January, and ... it was "decided" that it was ... inaccurate, and that there seemed to be no calibration or adjustment possible.

If that temperature value is actually used by the car to manage Climate Control, it could easily cause some strange operation.

If it is used for nothing, it is just (mostly) useless.

Do we have any further info from Nissan about this "defect"?

Here's the pertinent info from the service manual:

OUTSIDE AIR TEMPERATURE DISPLAY

OUTSIDE AIR TEMPERATURE DISPLAY : System Description INFOID:0000000006959382

SYSTEM DIAGRAM


DESCRIPTION
• VCM transmits a ambient sensor signal to the combination meter via CAN communication.
• ABS actuator and electric unit (control unit) transmits a vehicle speed signal to the combination meter via CAN communication.
• The combination meter calculates the outside air temperature based on the signals received from VCM and ABS actuator and electric unit (control unit) via CAN communication.
• The combination meter sends the calculated outside air temperature signal to the upper meter via the communications line.
• The upper meter indicates the outside air temperature according to the outside air temperature signal received from the combination meter by means of communication line
NOTE:
• The indicated temperature is corrected based on an ignition signal, ambient temperature detected by the ambient sensor, and vehicle speed signal. The indicated temperature is not raised under vehicle speed less than 20 km/h (12 MPH).
• The ambient sensor input value that is displayed on “Data Monitor” of CONSULT is the value before the correction. It may not match the indicated temperature on the outside air temperature display.
• Depending on motor heat or heat on the road surfaces, an ambient temperature may be indicated higher than actual one

SIGNAL PATH

I've noticed that too, genrerally 3 to 5 degrees low. And after this April, I need all the warmth I can get. Also, carwings has been dead since April 22nd. Called customer support yeaterday to try and get it reset. Told to wait 24 hours but still dead today.

Mine seems pretty accurate, maybe 1* off sometimes.

I've posted this elsewhere but I've found that it's not inaccurate, just heavily dampened in one direction (cold to warm) and dependent on vehicle speed. So it may appear inaccurate.

Thanks for the Service Manual info.
Maybe the "correction" calculation is ... peculiar?

More Info:
The LEAF-Savy Tech today said that the temperature only updates about once a minute, assuming the car is moving fast enough, showing the average of the current and previous readings. This means that it will take 5 minutes or so for the temperature to stabilize, and that the reading should "jump" once a minute toward the real outside temperature.

Knowing this, I will have to watch closer, for any "jumps", and for more accurate values. More later.

garygid said:

Thanks for the Service Manual info.
Maybe the "correction" calculation is ... peculiar?

More Info:
The LEAF-Savy Tech today said that the temperature only updates about once a minute, assuming the car is moving fast enough, showing the average of the current and previous readings. This means that it will take 5 minutes or so for the temperature to stabilize, and that the reading should "jump" once a minute toward the real outside temperature.

Knowing this, I will have to watch closer, for any "jumps", and for more accurate values. More later.

Click to expand...

This is true. I've replaced the temp sensor with a fixed resistor and observed the behavior.

http://www.mynissanleaf.com/viewtopic.php?p=64588#p64588

garygid said:

Thanks for the Service Manual info.
Maybe the "correction" calculation is ... peculiar?

More Info:
The LEAF-Savy Tech today said that the temperature only updates about once a minute, assuming the car is moving fast enough, showing the average of the current and previous readings. This means that it will take 5 minutes or so for the temperature to stabilize, and that the reading should "jump" once a minute toward the real outside temperature.

Knowing this, I will have to watch closer, for any "jumps", and for more accurate values. More later.

Click to expand...

this is what I've observed, esp on warm days. It can be 15-20 degrees off and then after about 10 mins. it seems to stabilize.

Accurate for me. In my other car correct temperature will not be shown right away, it takes about 15 minutes to get the reading. Probably the same case with Leaf.

so it factors in wind chill derived by a signal from the ABS sensor?

Mine too seems to be off also(10-15 degrees), I will look to see if it fixes itself after few minutes. On my other car its usually off also when you first start to drive, but it reaches correct temp in less than a minute.

malloryk said:

this is what I've observed, esp on warm days. It can be 15-20 degrees off and then after about 10 mins. it seems to stabilize.

Click to expand...

Yep . . . . numerous times it's been in the high 80's (for HOURS) and low 90's ... yet the car will read 69 degrees. sheesh. oh well

The car has to be MOVING for the temperature to be updating (gradually getting closer to correct?).

i wonder if the temperature range changes the accuracy. i used to think mine was relatively accurate. but on Sunday coming home from work after car sat all day in parking lot, it was reading 62º and it was at least 70.

i figured it would be like the Prius except in reverse and after a few miles the correct temperature would display, but i drove a bit and it dropped to 58º

i mean it was not even close!

i wonder if the temperature range changes the accuracy. i used to think mine was relatively accurate. but on Sunday coming home from work after car sat all day in parking lot, it was reading 62º and it was at least 70.

i figured it would be like the Prius except in reverse and after a few miles the correct temperature would display, but i drove a bit and it dropped to 58º

i mean it was not even close!

nader said:

so it factors in wind chill derived by a signal from the ABS sensor?

Click to expand...

Why would an inert object like this factor in 'wind chill'. Unlike humans, the sensor won't have evaporative heat loss. And unlike warm blooded mammalia, and we WANT the sensor to reach the ambient temperature, we don't care if it is deviating from 98.6F.

It may be that the sensor is in an area that is poorly ventilated with outside air until a specific speed is reached.

Like the others, my sensor can be way off for the first few minutes. That might not seem like a huge problem, but every other automotive thermostat I've ever seen has been faster to read actual temps than this one.

IMO, Nissan needs to put this on the 'needs improvement' list.

I'd put it on the "who cares" list. The Prius is the only car I ever had with an outside temp gauge, and the only attention I ever paid to it was that I would occasionally laughingly complain that all I care about is the inside temperature.

Ray

The Leaf has a poor excuse of an outside temperature gauge and I wonder if it will confuse the A/C system when it is quite hot outside and it reads 10-15 deg too low. They really need to improve the response time with slight degradation in accuracy if at all. Hopefully they will fix it through some software/firmware upgrade soon. This is a lot easier to fix than the 2nd gen Prius "fuel bladder" issue which would had a highly pessimistic fuel gauge.

planet4ever said:

I'd put it on the "who cares" list. The Prius is the only car I ever had with an outside temp gauge, and the only attention I ever paid to it was that I would occasionally laughingly complain that all I care about is the inside temperature.

Ray

Click to expand...

I'd agree, but I have another Nissan (2007 Murano) with a temperature gauge that works perfectly. Yes, if you park in the sun, it will read a little high, but will correct within perhaps one mile of driving.
The temperature gauge on the Leaf is laughably wrong, and often in ways that are counter-intuitive (e.g. says "69" after parking it in the 80-degree sun mid-day), and it takes much longer to 'correct' than my Nissan Murano's gauge.

So this is an example of Nissan taking an accepted, stable, apparent non-EV-related accessory (think headlights, or horn), and screwing it up vis-a-vis their own ICE-powered vehicles. I never expected that the Leaf's temperature gauge would be an improvement over the Murano, but I certainly didn't expect it to be demonstrably worse.

Is this nit-picking, on the order of "my 2 dashboard clocks don't match?" - yes. But it's frustrating to me because Nissan got so much "right" with the Leaf.

Mine is about 15 degrees off, my AC seems inaccurately controlled as well. Kind of a big joke since my 05' Tacoma temp sensor is always accurate, my clock is dead on, the standard stereo is better than the LEAF, etc, etc. As a first time Nissan owner I really question their tech abilities and vendor choices.