TPMS "Tire Pressure Low" error message on all four wheels... what are the odds all 4 tires are low?

[SeanM]

For those who are saying about TPMS.. I have another vehicle that does have TPMS on which I do at time (seldom though) get low tire pressure warning, but that warning disappears once I drive for few miles. But, today morning my Model-3 still shows low tire pressure, after driving for some miles.

For those who are saying about checking tire pressure and add more air if reqd., I do regular check on all my vehicles. I had added air (43 psi) to the Model-3 tires a couple of (it was a bit warmer than today) weeks back & all was fine until today morning when it showed 37 psi & climbed only up to 40 psi after driving a few miles. Am not sure if I should add more air to it.

Hence, am in a dilemma.

 

[dhanson865]

For those who are saying about TPMS.. I have another vehicle that does have TPMS on which I do at time (seldom though) get low tire pressure warning, but that warning disappears once I drive for few miles. But, today morning my Model-3 still shows low tire pressure, after driving for some miles.

For those who are saying about checking tire pressure and add more air if reqd., I do regular check on all my vehicles. I had added air (43 psi) to the Model-3 tires a couple of (it was a bit warmer than today) weeks back & all was fine until today morning when it showed 37 psi & climbed only up to 40 psi after driving a few miles. Am not sure if I should add more air to it.

Hence, am in a dilemma.

Set your tire pressure in the morning when the tires are the coldest they'll be all day. Must not have driven in the last 4 hours, preferably longer. Also good to not have 2 of the tires in direct sunlight and 2 in shade.

Set them when cold and ignore how much they go up when they get warm during the same day. Don't go changing your tire pressure multiple times a day or multiple times a week.

If you are at 37 in the morning and your correct PSI is 42 it doesn't matter what the PSI was in the afternoon or while you are driving. You need to add air.

 

[RC2785]

If you don't know if it's busted or not just check it with a tire pressure gauge.

 

[Big Dog]

as a general rule, you will lose 1 lb of pressure for every 10 degree temp drop.

 

[KKman]

I had this about a month ago. Tried rebooting the system but the sign was still there. Pump all 4 tire pressure to 43 and the sign does not show anymore. Still don't know why it thinks 40 psi is too low, especially when the other 3 tires are at the same pressure....

 

[SageBrush]

I get the same thing every winter. When the temperature goes below 50 at night you're going to need some more air in all your tires. It's completely normal. If you want the exact science Boyle's law - Wikipedia .

Wrong law, we want Gay-Lussac’s Law which says that if volume is constant, pressure changes are proportional to temperature.
If the temperature drops 10%, the pressure drops 10% ...
The trick here is to use kelvin since the scale has to start at (absolute) zero.

If the AM temperature was say 40F and afternoon is 80F then the temp dropped from 300k to 277k, a 8% drop. If the tyre pressure was 40 psi in the afternoon, it would be 40*277/300 = 37psi in the AM.

Questions ? Tweet Tom Brady. He knows all about this stuff.

 

[jat255]

Questions ? Tweet Tom Brady. He knows all about this stuff.

I'm always surprised that people don't realize that the pressure of things changes with temperature:

 

[davewill]

...
Hence, am in a dilemma.

No dilemma. Check your tire pressures, then you'll know.

 

[SammichLover]

I had this about a month ago. Tried rebooting the system but the sign was still there. Pump all 4 tire pressure to 43 and the sign does not show anymore. Still don't know why it thinks 40 psi is too low, especially when the other 3 tires are at the same pressure....
View attachment 464149

Tesla has chosen to have a very narrow window for “acceptable PSI”. My past vehicles have generally triggered on about 8 PSI off from factory default. Tesla only about 5 PSI off.

Your door probably has a sticker with 45 PSI as the correct pressure. This is probably the target PSI your car is set to maintain. ((Some Model 3s come with 42 PSI stickers but I don’t think the factory software settings are set to match that, AFAIK they all come expecting 45 PSI))

There are at least a few threads discussing what’s the most appropriate tire pressure. I personally target 40 PSI cold (although I have tires somewhat different than stock) and don’t get an error thrown. No warning even when one dropped as low as 36 PSI during the season change, before I topped them back up to 40 PSI cold.

This is because I have changed the PSI checkpoint level, via the software feature that came out about 6 months or more ago.

 

[SeanM]

Greetings Folks,

As I mentioned, I had checked and added (43 psi) the air to all tires a couple of weeks back. So, last evening while returning from my job, I rechecked/refilled the air in all tires. Then after driving for few mins, the ' tire pressure low' sign went away.

I decided to add air in evening as opposed to morning time, because wanted to have air temp inside to be highest in this weather. This way I won't be adding more than required air in the tires... though the tire pressure numbers are all over the place, see photo.

 

[SammichLover]

Greetings Folks,

As I mentioned, I had checked and added (43 psi) the air to all tires a couple of weeks back. So, last evening while returning from my job, I rechecked/refilled the air in all tires. Then after driving for few mins, the ' tire pressure low' sign went away.

I decided to add air in evening as opposed to morning time, because wanted to have air temp inside to be highest in this weather. This way I won't be adding more than required air in the tires... though the tire pressure numbers are all over the place, see photo.
View attachment 464554

The advice you are getting to set your tire pressure when they are cool is the correct path, unless you’re at the track where your operating temp range is very narrow (and hot), and you’ve got the tools & time handy to micromanage it.

Uneven rising and falling is a sign you have water in your tires. Water creates a much higher swing in PSI over temp changes as the moisture converts to/from liquid from/to gas.