Tire pressure warning

[LukeCooper]

Hey, I fill the tires to 45 as recommended. They usually never stay at 45 and quickly drop to 41 range, however the back right always drops more. It will fluctuate from 33-38 while driving even after the car is heated up, even after I fill it the warning of low tire pressure is still there. Now the back left dropped to 41 and gave me the warning, where as front left is 41 and there is no warning? What is going on just bad sensors? The back right has nothing punctured into the tire, I have to jack it off and see if there is anything on the inside of the tire behind the wheel where I cannot see.

 

[DerbyDave]

After inflating all tires when cold to the correct pressure, reset the Tire Pressure Monitoring System:
1. Inflate all tires to their recommended
pressures, as indicated on the Tire and
Loading Information label located on the
door pillar.
2. Get ready to drive for ten minutes, then
touch Controls > Service > Reset TPMS
3. Follow the onscreen instructions.

After recalibration, your tires should be monitored equally. The warning only goes off when tires are significantly underinflated or overinflated. If the calibration is off on front showing 41, it may not give you a warning.

 

[jmaddr]

I have to jack it off and

Eh....I love my Tesla as much as the rest but eh.....

Seriously, my only advice would be to verify. After you fill to 45, test with a known good portable guage (not those cheap pen ones) and verify all are at 45. Most have bleed pins on them so fill to 46 and then bleed to 45 to make sure they are all the same. Then go driving and when you get the error check them with the same gauge (keep it in your glovebox). If you confirm that the pressure is indeed as low as 33 psi and you have verified twice there are no punctures, it could be your rim. Check for cracks and if you find one, change it ASAP. I guess it could also be your valve but I rarely see those go bad.

 

[Ostrichsak]

Hey, I fill the tires to 45 as recommended. They usually never stay at 45 and quickly drop to 41 range, however the back right always drops more. It will fluctuate from 33-38 while driving even after the car is heated up, even after I fill it the warning of low tire pressure is still there. Now the back left dropped to 41 and gave me the warning, where as front left is 41 and there is no warning? What is going on just bad sensors? The back right has nothing punctured into the tire, I have to jack it off and see if there is anything on the inside of the tire behind the wheel where I cannot see.

Tire pressure is affected by ambient temperature. The higher the temp (also caused by friction from higher highway speeds) the higher the pressure. The opposite is also true of lower temperatures, naturally.

Our local Discount Tire has a fill line that you can hop in for free and you tell them a number. If I tell them "45" it tends to leave me in the 41-42 range. If I tell them "47" it tends to put me right on the money. You will need to alter this if you plan to do a longer highway trip. I will tell them "45" if I plan to drive hours on the highway at 80mph so pressure doesn't get too high once the tires are at temp. If there's a cold front coming in I will probably tell them "47" as it will be lower. The shoulder months in some areas can be a real PITA as you are constantly adjusting but it's good practice to stay proactive on tire pressure as it increases safety and tread life quite a bit.

This all assumes that the tires are dropping equally though, I'd say within 1-3psi of variance from tire to tire. If it's one tire specifically that loses more pressure (mine on all of my cars stay with 1-2psi of each other) you may have a nail or screw stuck in it or possibly even a cracked wheel. These heavier cars are known for that especially on the 21's that have less sidewall to help absorb the impact of a pothole or something. Tire shops can check it for a foreign object or possibly even dunk it in a tank to find a cracked rim or other puncture leak if nothing is visibly apparent. Might be worth looking into if it's continuously one that drops pressure 5+ psi compared to the others.

 

[Tdriver]

Don't know the age of your car but the age of the batteries on the sensors is not infinite.

 

[Ostrichsak]

Don't know the age of your car but the age of the batteries on the sensors is not infinite.

When the battery dies they don't read a different/inaccurate reading, that specific sensor just no longer communicates with the TPMS module and needs to be replaced.

 

[P100D_Me]

To the OP, not sure what year you have there but on my car the TPMS is pretty flaky (has been from day one).
I've seen warnings for low pressure showing the wheel with the issue as the one that doesn't actually have the lowest pressure
It is also guaranteed on my car that after doing some highway driving I get a TPMS warning, pressures are all mornal in the display, it just comes up on the cluster with a warning about the TPMS....I've just put it down to another Tesla software quirk.

 

[DerbyDave]

And all of this is after you recalibrate the TPMS system? I don't know of any other issues with these generic TPMS sensors in other car brands. This isn't rocket science.

 

[Barry]

If I tell them "45" it tends to leave me in the 41-42

Your issue is altitude-related. In the Denver area, the TPMS will read 3 psi low. This is because the TPMS has no external reference. There's a lengthier scientific explanation somewhere on the tirerack.com web site.

Bottom line, along the Front Range, you have to add 3 to what the TPMS reads. I've verified this with a calibrated pressure gauge. Your other option is driving to sea level and reset/calibrate the TPMS there

 

[Ostrichsak]

Your issue is altitude-related. In the Denver area, the TPMS will read 3 psi low. This is because the TPMS has no external reference. There's a lengthier scientific explanation somewhere on the tirerack.com web site.

Bottom line, along the Front Range, you have to add 3 to what the TPMS reads. I've verified this with a calibrated pressure gauge. Your other option is driving to sea level and reset/calibrate the TPMS there

Good to know but the problem is that if I fill to 45psi (indicated) this means that it will read 41 or 42 which is a mere 1 or 2psi away from triggering the low tire warning alert(s). I wish Tesla would adjust the alarm via software down that 3psi for those at elevation to offset this phenomena.

 

[Barry]

Good to know but the problem is that if I fill to 45psi (indicated) this means that it will read 41 or 42 which is a mere 1 or 2psi away from triggering the low tire warning alert(s). I wish Tesla would adjust the alarm via software down that 3psi for those at elevation to offset this phenomena.

You're right. I've had plenty of times where the low pressure indicator has come on. Drive for a while, the tires warm up, and the warning goes away.

 

[Prowler]

After inflating all tires when cold to the correct pressure, reset the Tire Pressure Monitoring System:
1. Inflate all tires to their recommended
pressures, as indicated on the Tire and
Loading Information label located on the
door pillar.
2. Get ready to drive for ten minutes, then
touch Controls > Service > Reset TPMS
3. Follow the onscreen instructions.

After recalibration, your tires should be monitored equally. The warning only goes off when tires are significantly underinflated or overinflated. If the calibration is off on front showing 41, it may not give you a warning.

Thank you for info.