Low tire pressure warning

[churin]

The warning display popped up while driving today. I parked at destination and about one hour later when I restarted the vehicle the warning no longer reappeared. Does this mean it was a false warning?
The wheel size is 20". Warning is for right front tire. After I got home the pressure was measured 39psi. Pressure of other three range 39.2 to 39.5.

 

[Big Earl]

The warning display popped up while driving today. I parked at destination and about one hour later when I restarted the vehicle the warning no longer reappeared. Does this mean it was a false warning?
The wheel size is 20". Warning is for right front tire. After I got home the pressure was measured 39psi. Pressure of other three range 39.2 to 39.5.

You’ll probably want to bring the pressure up a few more pounds. I’m running 50 right now, but I should probably bring them back down to around 45. Great efficiency at this pressure, but a little squirrelly in the rain.

 

[StealthP3D]

The warning display popped up while driving today. I parked at destination and about one hour later when I restarted the vehicle the warning no longer reappeared. Does this mean it was a false warning?
The wheel size is 20". Warning is for right front tire. After I got home the pressure was measured 39psi. Pressure of other three range 39.2 to 39.5.

Why do you run them so low?

 

[churin]

My point is:
1. Is the warning false because it did not stay and disappeared?
2. Are the pressures as measured low enough so that I should concerned about or raise the pressure?

 

[StealthP3D]

My point is:
1. Is the warning false because it did not stay and disappeared?

This is impossible to determine since you didn't measure the pressures when the alert occurred. Generally the sensors are pretty reliable but you are running pressures pretty low so I would say it was probably not a false alert.

2. Are the pressures as measured low enough so that I should concerned about or raise the pressure?

You never explained why you are running pressures so low (but I can't imagine a good reason unless your tires are unique). By raising the pressure you will be less likely to pick up nails and screws (flat tires), you will have more responsive steering, longer tire life, better range and quicker charging and reduce cycling of your battery. Your rims will also be better protected if you accidentally hit moving or stationary debris in the road or a bad pothole at speed. You will also be less likely to have a flat tire caused by such an impact.

You should measure the tire pressure first thing in the morning, not after driving them through the heat of the day. That's why the recommended pressure is stated as "cold" pressure.

 

[JulienW]

....just to add pressure is dynamic and changes with ambient temperature and driving conditions. I think about 36PSI is the point that the warning appears which seems is a little high for a low pressure waring but.......

 

[N54TT]

The warning display popped up while driving today. I parked at destination and about one hour later when I restarted the vehicle the warning no longer reappeared. Does this mean it was a false warning?
The wheel size is 20". Warning is for right front tire. After I got home the pressure was measured 39psi. Pressure of other three range 39.2 to 39.5.

I’m guessing the the warning came on at the beginning of your drive? You need to measure the pressures when the tires are “cold”. In the morning before you start driving...and before the tires are sitting in the sun. You’re probably at the cusp of what sets the warning off. After driving and the tires sitting in the sun..the pressures increased and stayed above that...hence why you didn’t get the warning an hr later. It’s probably not a false warning.

 

[qdeathstar]

I also had this warning pop up yesterday.... haven’t checked my psi yet as it happened right as i was getting home... but the tires looked fine,

 

[turnem]

I've had this happen as well. I think rapid changes in temperatures or barometric pressure can do it. It happened to me while driving in the mountains. It went away after a while.

As long as the message doesn't persist for a day or so you can chalk it up to odd swings in the environment that is throwing a false warning.

 

[qdeathstar]

Looks like I’m running at 37 psi! Time to bring the compressor out...

 

[churin]

The car was parked in garage. The warning came on in about 20 minutes after driving out, arrived at destination, parked in a roofed parking space(inside parking lot at a mall), after one hour started driving back home but no warning came back.
The above does not appear make sense because there was no low pressure warning before started driving and pressure should go only upward after driving began. Also, while parking at the destination tire pressure goes only downward, yet no warning when the vehicle restarted. There was no significant altitude change between my house and the shopping mall(destination).

There are replies in this thread indicating why running pressures so low in response to my reported 39psi. The wheel is 20" with stock tires and nothing special. How high the pressures should be because 39psi does not seem alarmingly low considering recommended 42psi.
At this point in my writing this post, it occurred to me that I should measure the pressure after the car is parked in garage over-night.
It is now 35psi. Well, this is definitely too low. But is this normal? I did not measure it when I took delivery so I never know how much psi reduction happened since. I took delivery of this car on 10/11/2018 and have driven so far for 3500.
I wonder why I never feel this much low pressure when driving. I normally feel low pressure condition with my other non-Tesla car and previous cars.

 

[JulienW]

....The warning came on in about 20 minutes after driving out,...The above does not appear make sense because there was no low pressure warning before started driving....I wonder why I never feel this much low pressure when driving. I normally feel low pressure condition with my other and previous cars.

This is easy. No measurement is taken until after you are driving for certain amount of time. Just try looking at the Card while parked.

Also you will NOT feel it because we have higher pressure in the tires. This is for efficiency and the high weight. It starts to indicate low at 36PSI and this is higher than many cars when correctly inflated. A common PSI number is 32PSI. To feel it low it would need to be down to about 20PSI or less.

 

[churin]

This is easy. No measurement is taken until after you are driving for certain amount of time. Just try looking at the Card while parked.

I did not measure before driving out the car parked in my garage overnight. But when the alert was displayed the pressure must be higher. Why the alert when pressure is going up?

 

[JulienW]

I did not measure before driving out the car parked in my garage overnight. But when the alert was displayed the pressure must be higher. Why the alert when pressure is going up?

Again it doesn't do ANY measurement until after you have been driving for a while. Open your Card and you will see there is no measurements until after you have driven for a little bit and up to speed. You will see -- as your measurement while in your garage and after you start driving.

 

[Big Earl]

I also had this warning pop up yesterday.... haven’t checked my psi yet as it happened right as i was getting home... but the tires looked fine,

You know you can check the tire pressures from the screen, right? Swipe left.

 

[qdeathstar]

You know you can check the tire pressures from the screen, right? Swipe left.

Imagine how derpy i felt once i got in my car this morning to head to work....

 

[N54TT]

The car was parked in garage. The warning came on in about 20 minutes after driving out, arrived at destination, parked in a roofed parking space(inside parking lot at a mall), after one hour started driving back home but no warning came back.
The above does not appear make sense because there was no low pressure warning before started driving and pressure should go only upward after driving began. Also, while parking at the destination tire pressure goes only downward, yet no warning when the vehicle restarted. There was no significant altitude change between my house and the shopping mall(destination).

There are replies in this thread indicating why running pressures so low in response to my reported 39psi. The wheel is 20" with stock tires and nothing special. How high the pressures should be because 39psi does not seem alarmingly low considering recommended 42psi.
At this point in my writing this post, it occurred to me that I should measure the pressure after the car is parked in garage over-night.
It is now 35psi. Well, this is definitely too low. But is this normal? I did not measure it when I took delivery so I never know how much psi reduction happened since. I took delivery of this car on 10/11/2018 and have driven so far for 3500.
I wonder why I never feel this much low pressure when driving. I normally feel low pressure condition with my other non-Tesla car and previous cars.

Pressures don’t update/read/display until after you start driving. Once warmed up it takes time (more than an hr) for the pressure to drop back down to “cold” pressures....even if it’s not in the sun.

 

[churin]

Pressures don’t update/read/display until after you start driving. Once warmed up it takes time (more than an hr) for the pressure to drop back down to “cold” pressures....even if it’s not in the sun.

Are Tesla cars unable to measure or detect their tire pressures before they get out of garage in the morning even their electrical system are turned on? Then, the low pressure alert systems appears useless. It is hard to believe.

 

[Magnets!]

The warning display popped up while driving today. I parked at destination and about one hour later when I restarted the vehicle the warning no longer reappeared. Does this mean it was a false warning?
The wheel size is 20". Warning is for right front tire. After I got home the pressure was measured 39psi. Pressure of other three range 39.2 to 39.5.

After you set the pressure, reset your TPM...chances are the TPM is still set for 42 or 45 psi unless you have reset it. I disagree with others here that 39 is 'so low'. I run 39 and feel that it's the ideal pressure. Plenty of similar weight vehicles are spec'd for air pressure in the 30s. Efficiency gains by running 45+ are quite small.

 

[N54TT]

Are Tesla cars unable to measure or detect their tire pressures before they get out of garage in the morning even their electrical system are turned on? Then, the low pressure alert systems appears useless. It is hard to believe.

Yes it won’t detect it until you start driving. It does it fairly quick within a minute - few minutes .....but not until you start driving. There typically won’t be a drastic change in those first couple minutes. But if you want the most accurate “cold” pressure to the 10th, you need to check it in the morning or after it’s been sitting for a couple hours and before you start driving. I wouldn’t call it useless...you did get a tire warning. Where it doesn’t help is if you have a flat and don’t notice it before you start driving.

If you don’t believe it....swipe left over to the pressure monitor screen before you put it in drive and start driving.... and see when it updates/registers.