Outside temperature not changing

[hondaero]

hi,

i'm facing an issue with outside temperature not updating according to reality.
e.g. the initial temperature ( from garage ) remains unchanged when going outside in full sun. the gap can be very big: e.g 17 C on cluster vs. 27 C in reality.

i could leave with it however i wonder whenever there're implications on climate control system and / or battery management.

i've checked the climate control's history DTCs and no error reported. moving forward, it would mean removing the outside temp sensor to test. unfortunatey this locates in the front bumper and requires lot of workshop not to speak about potential car damages which might occur.

any ideas on fixes / checks / or workarounds are appreciated.
thank you,
~amo~

[MaXPainT]

Does it not change at all or it takes a lot of time to start changing? I park mine in an underground garage daily. It takes at least 10 minutes of driving outside for the temperature to start updating. It has been like this since the beginning.

[hondaero]

It does NOT change for even longer periods of time e.g. 20-30+ minutes.

Today, I've run the climate control system procedure to read sensors' inputs:
- climate control reading : outside temperature 20 C
- on cluster : outside temperate 16 C !!!

At this stage, it seems more like a cluster software issue however more investigations would be required.

Any ideas how I should proceed is appreciated.
thanks
~amo~

[hondaero]

Additional information on this topic (e.g.):
- on CAN bus reported temperate: 13 C;
- on cluster temperate: 13 C (so cluster reflects correctly the temperature reported on the car's bus);
- climate control outside sensor reading: 20 C.

There is a service bulletin "Gauges Symptom Troubleshooting - Outside air temperature indicator does not change 1601" which might indicate I'm NOT the only one seeing this issue. As fix, they're indicating removing and testing the sensor itself which seems indeed difficult due to sensor location.

Anybody else having the same issue and can share more about fixing / solving this ?

Thanks,
~amo~

[Deleted User 473]

It does sound like a software issue more than anything.

The only option available to you is to reset the infotainment possibly, but I can't imagine that it is involved. I suspect that the single sensor value is used by multiple modules (dash, climate, charging etc), so perhaps there is some module responsible for multiplexing its output?

If the raw data can be read over the scan tool, then the sensor must be physically working...

Have you tried removing the 12v for a while so as to cold reboot everything?

[hondaero]

thanks for your reply however i won't go for a reset - at least for now - as i would prefer to understand the situation and have a potential root case & fix.

Outside Air Temperature has 3 operational modes - 1. initial indication, 2. traffic jam mode, and 3. stable run mode. the last implies the car should reflect / adjust to the real temperature every 30 seconds which is definately not my case. indeed, most likely a software issue.

thanks
~amo~

[Deleted User 473]

I can confirm that the car should respond to outside temperature changes after the journey has started. I often start my journeys at one temperature, and less than 30 minutes later it is a few degrees higher/lower (morning commute on cold english morning, car is parked outside overnight).

As for your approach to trying to find the cause, I would give up trying to understand (And I mean that in the nicest possible way). The car is simply a collection of inscrutable black boxes and wires connecting them, the operation of which is unknown (not documented) and as to how those operations are implemented is also unknown (no code base for the modules available, no way to emulate, or inspect in-situ / in-circuit). We don't even have publicly available block diagrams of systems (real or software).

At least with a 12v reset, the 'system' gets put into a supposedly known/consistent state, which makes testing consistent/reliable. The first step in testing is generally to try and reproduce it. If the end goal is to find a fix, then off and on again is high on the list of things to try.

My real life experience is that you are better off 'attacking' such a problem, rather than try to understand it. The reason I say this is you can affect no change in the modules.

[hondaero]

thank you for your reply and i understand the approach and true advice.

in 30 minutes I might see also a change of the temperature, however in my other cars the temp changes rather quickly and follows the road / weather conditions. not the case with my Honda.

i've decided to visit the dealer to investigate on this. it will be on 13.05. i'll post here the outcomes / next steps.

~amo~

[Deleted User 473]

ah, I see. The opening post read as if the temperature is simply stuck on one reading...

If you have a lag on the sensor, then most likely it is insulated with dirt or similar, or perhaps not getting airflow to it. Did I read that your vehicle is wrapped? Is it possible that one of the vents for the sensor is covered, and so it takes a long time to conform to the true ambient temperature?

Since my vehicle is parked outside, I do not have much of a differential to assess how quickly it changes when there is a big change in ambient. I will try to check it next time i park in a warm underground car park on a cold day.

[hondaero]

no wrapped vehicle here ... it is the original red from Japan
also, my car is quite spoiled, no driving in bad weather, etc so the dirt or similar shouldn't be the cause.

thanks for checking it at your end,
~amo~