TPMS warning hours afterdriving

[Mark57]

Last night my wife got a notification on her phone that one of her tires was at 24 PSI on her 2021 M3LR, 5 hours AFTER she had last driven. All the others were @ 42 PSI. TeslaFi shows the car was sleeping. It was plugged in but not charging, sitting in the garage. Her tire pressures were normal when she got home per TeslaFi. She'd run over a long screw and it was leaking while sitting in the garage. Sure enough, that tire was at 24 PSI. I had to air it up to get the floor jack under it. I know you have to move the car or spin the tires to wake up the TPMS and see the pressures. I play this game with both our M3's when I try to adjust for changing seasonal temps. We had a flat on the Interstate in my car a few months ago, and this is the exact same warning, low pressure stop pull over, etc. She got the phone notification and when I went out to check it, she also had the pressure warning inside the car.

This alert is great, BUT it goes against everything I "thought" I knew about the Model 3 TPMS. She's on ver 2023.12.1. If it wasn't such a pain to get all 4 tires the same, I'd let the air out of one of my tires on my M3LR (ver 2023.6.8) just to see if I get an alert. Has anyone else seen this?

If this is a change, it's a great one. You'd know about a flat or low tire ahead of time. Which is exactly what happened.

 

[Benito1283]

I noticed this the other day too. I was having my car alignment and they inflated the tires to the recommended 42 PSI. I was creeping in the app and saw it registered the increased pressure in the two rear tires, even though I could see the car just sitting on the alignment rack.

Maybe the wheel spinning forces it to update, but it’s still possible for it to measure without spinning?

 

[Mark57]

Maybe the wheel spinning forces it to update

Yes, what you saw was normal, the wheel spin does cause an update, but ours happened 5 hours AFTER the last movement. I always though the TPMS was not active until moved to save battery, or at least that's what we all thought? It always acted that way before, but I never had this exact circumstance before.

 

[Benito1283]

Yes, what you saw was normal, the wheel spin does cause an update, but this happened 5 hours AFTER the last movement.

Maybe that’s when the PSI crossed the threshold for an app alert?

 

[Mark57]

Maybe that’s when the PSI crossed the threshold for an app alert?

Yes, certianly. It's the time frame that is the big question.

 

[Benito1283]

Yes, certianly. It's the time frame that is the big question.

It was slowly leaking? Maybe I’m unclear what you’re wondering. Does it seem weird because the car was sleeping?

 

[Mark57]

It was slowly leaking? Maybe I’m unclear what you’re wondering. Does it seem weird because the car was sleeping?

OK, TPMS is active when the car is moving. It goes to sleep about 1 minute after the tires stop moving. Like when you park for longer than . . . 1 minute. As many posts here have said, TPMS is not awakened until the tires rotate. Her car had been parked, not moving for 5 hours when she got the alert. That implies TPMS was awakened by the pressure drop and sent the alert. If true, this is something completely new.

Therefore I ask, has anyone seen this before or are we seeing something new.

 

[Benito1283]

OK, TPMS is active when the car is moving. It goes to sleep about 1 minute after the tires stop moving. Like when you park for longer than . . . 1 minute. As many posts here have said, TPMS is not awakened until the tires rotate. Her car had been parked, not moving for 5 hours when she got the alert. That implies TPMS was awakened by the pressure drop and sent the alert. If true, this is something completely new.

Therefore I ask, has anyone seen this before or are we seeing something new.

Yes I see. That’s why I said I actually experienced the same exact thing. I saw the pressure update/increase in my app while my car was parked on a lift, wheel not spinning.

I suspect your situation was the exact purpose this was intended for. But I too am surprised it would track tire pressure, especially when sleeping.

 

[BigNick]

Maybe the pressure change was enough to "wake" the TPMS sensor in question?

 

[Mark57]

Maybe the pressure change was enough to "wake" the TPMS sensor in question?

That's what I'm thinking. I'm hoping this is the case because it saved me from fixing a flat under spouse pressure at 4am and made it a leasurly flat fix at 9pm. I've read other discussions about people "wishing" it would do that, but I've not found anyone saying it did. I'm going to test it on my M3LR this afternoon.

 

[DeltaOne]

That's what I'm thinking. I'm hoping this is the case because it saved me from fixing a flat under spouse pressure at 4am and made it a leasurly flat fix at 9pm. I've read other discussions about people "wishing" it would do that, but I've not found anyone saying it did. I'm going to test it on my M3LR this afternoon.

This week I had to replace the tires on my wife's Toyota. The batteries on the tire pressure sensors were really low, so we replaced those as well. They say the TPMS batteries last 5 to 7 years, this car is a bit over eight years old.

It was my first experience with these sensors so I did some research on YouTube university. Your thinking is correct, the sensors will wake up and send alerts if there is a significant drop in air pressure.

Here's a video I liked, everything (and more) that you might want to know about tire pressure sensors.

 

[Mark57]

Your thinking is correct, the sensors will wake up and send alerts if there is a significant drop in air pressure.

I tested it myself this morning on my 2021 M3LR. Car had been in sleep mode all night. I deflated the tire manually, but I did not get a notification until I got to about 26 PSI. I'd have to look in the service menu to see that that threshold is set to.

Good part is I did get a low tire warning. without rotating the tire or moving the car. Great feature, confirmed. Hoefully it works the same for a very slow leak which is harder to simulate.

 

[avlstrike]

I'm not sure if this thread applies to me or not. I got a low pressure warning (25 PSI) for the left front while the car was parked and charging last night.
Nope - checked the tire with a gauge and it is 40 PSI like the others. Haven't moved it yet (nor done anything else), so don't know if it will change when
I drive it. Car is a 2023 Y LR AWD one month old.

Dave

 

[Mark57]

I'm not sure if this thread applies to me or not. I got a low pressure warning (25 PSI) for the left front while the car was parked and charging last night.
Nope - checked the tire with a gauge and it is 40 PSI like the others. Haven't moved it yet (nor done anything else), so don't know if it will change when
I drive it. Car is a 2023 Y LR AWD one month old.

Dave

Different situation from this thread. My reported pressure in the car and app matched the manual tire gage when I checked it. It was just that one tire that was low.

Move it and update the pressure car to see if it changes.

 

[avlstrike]

Different situation from this thread. My reported pressure in the car and app matched the manual tire gage when I checked it. It was just that one tire that was low.

Move it and update the pressure car to see if it changes.

Took a short drive this evening. Tire pressure went down to indicated 22 PSI at my destination, then to 21 PSI on return home. Gauge still reads 40 PSI (normal, and no change).

Dave

 

[Mark57]

Gauge still reads 40 PSI (normal, and no change).

Be safe and check all 4 tires with your manual gauge. These tires don't look low until they're VERY low. It's possible the tire that shows low on your vehicle screen is not the tire that's actually low. Be safe and don't assume.

You're driving a MY LR, but I'm pretty sure you can also do a reset on your TPMS sensors to make sure they indicate the correct positions like after a tire rotation. They're supposed to do this automatically after driving for 10 minutes over 15 mph.

If your manual pressure gauge check on all 4 tires is good, and you've done the TPMS reset and you've driven it 10-15 minutes, and it' still says the tire is low, you can do a power down reboot. Controls, Safety, Power Off. It needs to be off for at least 2 minutes. DO NOT touch anything inside the car while it's off. Use your phone to time it and hit the brake to wake it up after 2 minutes. Drive the car and see if that fixes the TPMS reading on that tire. If not, you may have a bad TPMS.

 

[avlstrike]

Be safe and check all 4 tires with your manual gauge. These tires don't look low until they're VERY low. It's possible the tire that shows low on your vehicle screen is not the tire that's actually low. Be safe and don't assume.

You're driving a MY LR, but I'm pretty sure you can also do a reset on your TPMS sensors to make sure they indicate the correct positions like after a tire rotation. They're supposed to do this automatically after driving for 10 minutes over 15 mph.

If your manual pressure gauge check on all 4 tires is good, and you've done the TPMS reset and you've driven it 10-15 minutes, and it' still says the tire is low, you can do a power down reboot. Controls, Safety, Power Off. It needs to be off for at least 2 minutes. DO NOT touch anything inside the car while it's off. Use your phone to time it and hit the brake to wake it up after 2 minutes. Drive the car and see if that fixes the TPMS reading on that tire. If not, you may have a bad TPMS.

Thanks for the info. Turns out the TPMS was indicating the wrong wheel. It had me checking the left front - when in fact it was the left rear that has the problem. Yep -it is a nail, and I found it by looking at the tires. I will try the TPMS Reset after I get the tire fixed.

Dave