Getting intermittent tire pressure alert

Getting intermittent tire pressure alert

Two days ago when I got in my car in the garage I got a warning that that the tire pressure was low.
The screen said it was 39 psi in all 4 tires.
Yesterday I got the same alert, but as I drove--and the tires warmed up on the road, the tire pressure went up, eventually to 42 psi in all 4 tires, but it was still giving me a yellow triangle with exclamation point alert popping up as I was driving. When I drove back home, the pressure was listed back down to 40, but there was no alert!
The door panel says that I should keep the tires at 42 psi.
It's been cold here in greater Boston the past few days, but not bitter cold, and as the temperature drops and rises, so will the tire pressure (and also football pressure, but I probably shouldn't go there!).
So, given that we've got a few more months of winter cold to go, what's the best strategy for managing my tire pressure?
And what's considered genuinely low, so that if it reaches that value I really need to take care of it quickly?
Thanks, GIl

AWDTesla | January 14, 2019

Add a few psi. Got the same warning this weekend when temps dipped to -20 Celsius. Every car will go through this when the colder climate hits.

msmith55 | January 14, 2019

Raise pressure to 42 psi as shown on door sticker , this applies in cold weather, in hot weather, lower pressure to 45 psi to 42 psi.

Bighorn | January 14, 2019

Add air

jordanrichard | January 14, 2019

Temperature changes will do this when there is a drop in temperature. Add air and monitor it. If that tire goes low again then there may be a slow leak.

gballant4570 | January 14, 2019

I'm keeping mine at 46-47 psi. When the weather cooled here I started getting the alerts - so I went up 4-5 psi. Efficiency improved a bit as well. I could not discern any difference in ride.

CST | January 14, 2019

Sometimes, one tire will trigger the warning with the same pressure in the other 3. I've even raised the pressure in the triggering tire 1 psi above the non-triggering ones, and the warning keeps showing on the higher-psi tire!
I believe once the trigger occurs, you have to raise that tire above the reset threshold (40psi?) to get the TPMS to stop annoying you.

gmartinez84 | January 14, 2019

I got the same issue last week out of nowhere. Thought I was getting flat. It wasn’t too cold outside 40-45°. It eventually went away after a few trips without adding air.

jeremynordland | January 14, 2019

I got the same message for my right front tire as I was driving. It said to slowly pull to the shoulder and inspect the tires. Only thing is, all tires showed 45psi, including the right front. It remained on for the entire drive (approx. 20 miles) and then was gone the next time I drove it and hasn't returned since. Odd...

Tuning In | January 15, 2019

There should be something that we can abbreviate that means “Do what you did with your ICE car”


007bond | January 15, 2019

For sure with low temp it will drop. I have been keeping them at 44 psi almost 10k miles never rotated the tires as yet and wear on all 4 looks even. I think the ride is good at 44 and as long as the tires are wearing even I am sticking with it.