ADAS not working at low temperatures

[FreddieC73]

Shortly after the first service (v90 T6 recharge, MY22, with AAOS) and upgrade to AAOSS 2.4 in November 2022, all ADAS (lane departure warning, pilot assist, collision mitigation) started working erratically. Some days they would not work, giving a warning and telling to book the car for a check, while on other days they would work perfectly. Immediately after the problem presented, I booked the car in - first slot available in mid December. The dealer suggested it may be a software related issue, caused by AAOS 2.4, which the car tries to fix by itself, resulting in the systems working intermittently. On the morning I was meant to take the car in, the electric heater stopped working, giving a “service required” error. The dealer diagnosed a broken heater, and said they could not update the AAOS and look at the ADAS issue until the heater had been replaced, as otherwise the software upload may have failed. Unfortunately, I am still waiting for the heater to be available from Sweden (it is on back order). In the mean time, I have kept a log of the functionality of ADAS, and noticed a clear pattern: when the outside temperature is below 6C, the systems do not work, while they work normally if it is above 6C. The inside temperature does not matter (ie if it is below 6C outside, and I warm the inside of the car, then switch off and on the car, the ADAS would still not work). Has anybody experienced something similar; if so, how was it fixed? I have a feeling of impending doom, and I anticipate great frustration and lot of visits to the dealer to sort out this problem. I have planned a long drive (1200 miles) for Easter, lots of motorway in France, so having pilot assist would be a great help. I am also unsure what would happen in terms of insurance in the event of a collision, if I drive a car which is not fully functional in terms of safety features! If the weather gets better before the heater is available, the dealer may even fail to reproduce the error, and I will be back to square one next winter. Thanks in advance

[giftgrub100]

Sounds like sensor in the windscreen is not able to see, put heating to windscreen, make sure your ac is on to de humidify the air and recirculation is switched off.

[FreddieC73]

Tried that- no difference. The system would kick in again only when the outside temperature is 6C or more- after a switch off/restart.
It is a very odd problem!

[ian77]

Pure hypothesis but the radar in the grille emblem is heated and I wonder if there is something not quite right with it? That could manifest as a cold weather only issue with those sort of systems.

I can’t work out why they would move the radar to the grille, surely behind the screen where it’s swept by wiper, is in the warm inside of the car and higher up is a better place 🤷

[FreddieC73]

Ok- finally the HVAC arrived, so today I brought the car in to replace the electric heater, update software and hopefully sort out the issue with the driving assistance systems.
In the meantime, while waiting for the spare to arrive, I “experimented” to find out what was causing the issue and I discovered the following (I hope nobody will ever experience the same problem, but just in case…):
- the measured external temperature when ignition is switched on is the key factor to trigger the malfunctioning; please note I said “measured”- you will understand why
- if I switch the ignition on and the external temperature is 6 C or above, everything works well, even if the temperature later drops below 6 while I am driving;
- if the external temperature is 5 C or lower, the ADAS will not work (no emergency braking, no lane assist, no cruise control, no pilot assist), even if the temperature increases above 6C while I am driving.
- now, the interesting fact, demonstrating that it is the measured temperature and not the actual temperature causing the problem. If I warm up the temperature sensor with my fingers before switching on the ignition (it is a little bulb poking out of the bottom part of the wing mirror), until the external temperature reading is above 6C (it will increase very quickly to 10C and above), the systems will work.
This means that this is unlikely to be a camera sensor issue directly caused by the cold temperature, or an electric contact caused by expansion/contraction; instead, for some weird reason, the external temperature lower than 6C triggers some kind of error that prevents the ADAS from working.
Given this issue appeared after upgrading to AAOS 2.4 (in November), the dealer was hoping that upgrading the software to the latest version (now I have 2.7) would solve the issue.
Unfortunately I have just discovered tonight that this is not the case … 😭
So, Monday I will have to call the dealer again, inform them and see what they suggest. I anticipate this will be frustrating, as this morning, when the temperature was 8C, they could not read any error.
The silver lining of the cloud is that I just need to touch the bottom part of the wing mirror for 10-15 seconds to fix the problem- still not really a permanent fix and certainly something I would expect not to happen!

[ian77]

Very strange! Have you tried the reverse - ie forcing an error by cooling the sensor with ice or something else frozen? If so then it would be reproducible at the dealer.

[Philip Fisher]

Originally Posted by ian77

Very strange! Have you tried the reverse - ie forcing an error by cooling the sensor with ice or something else frozen? If so then it would be reproducible at the dealer.

Not my problem, but that is an inspired idea.

[viraj]

Hello @FreddyC73, is this problem resolved?

[FreddieC73]

Unfortunately not… :-( presenting again now that the temperature has dropped, and fixed the same way (finger on temperature bulb for a few seconds).
Interestingly (for me, the Volvo engineer could not really care), the fault can be triggered by cooling the temperature probe even when the outside temperature is above 6C.
The fault appeared also this summer during a trip to Italy, when outside temperatures were in excess of 30C.
Last winter, the local Volvo dealer told me that VOlvo is aware of the issue and it is a software problem which should be fixed with the first update in 2024. I am not holding my breath. If somebody has the same problem, or knows a solution, please let me know!

[giftgrub100]

Just wondering is the temp on the dash correct or reading wrong also ?