[cadman50]

Not sure of the threshold where the warning will go off but if all 4 tires lose equal amounts of air then the warning never comes on. I was down 2 lbs in each tire and the warning didn't come on. What is the amount of air that a tire has to lose to set off the warning? And if all 4 tires get to that level at the same time will the TPMS warning system go off?

[Nahoa]

I'm not sure exactly what the difference is, but I believe it's fairly large. The system isn't intended to help you maintain proper inflation, it's designed to let you know when your tire has been compromised so it's looking for a larger change. Might even be looking for a change rate indicating a more rapid decline than normal loss.

[brissim]

I would have assumed that for those markets which have the direct TPMS system - ie directly measuring tire pressure - if you were to loose air at the same rate then eventually the alarm will come on. I would assume that this loss of air pressure would be way more than just 2 psi.

Its us who have the indirect TPMS system looking at balance differences between the wheels that would not pick up a loss of air pressure in all four tires.

For your info - and I don't know how this translates into the low air pressure alarm point in your direct TPMS - I currently have a slow leak in one tire with the alarm on our indirect TPMS coming up about once per week when the air pressure has fallen from its normal 36 psi to 27 psi.

Tony

[cadman50]

Originally Posted by brissim

I would have assumed that for those markets which have the direct TPMS system - ie directly measuring tire pressure - if you were to loose air at the same rate then eventually the alarm will come on. I would assume that this loss of air pressure would be way more than just 2 psi.

Its us who have the indirect TPMS system looking at balance differences between the wheels that would not pick up a loss of air pressure in all four tires.

For your info - and I don't know how this translates into the low air pressure alarm point in your direct TPMS - I currently have a slow leak in one tire with the alarm on our indirect TPMS coming up about once per week when the air pressure has fallen from its normal 36 psi to 27 psi.

Tony

that's quite a drop. I would have thought 3-4lbs max and the warning would come on. When the warning is activated, does the nav screen go to the TPMS screen and make one (or more) tires a different color? or do you get a 'ding-ding' sound and a yellow triangle on the screen in front of you?

[brissim]

Originally Posted by cadman50

that's quite a drop. I would have thought 3-4lbs max and the warning would come on. When the warning is activated, does the nav screen go to the TPMS screen and make one (or more) tires a different color? or do you get a 'ding-ding' sound and a yellow triangle on the screen in front of you?

For me (ie with the indirect TPMS) when the warning is activated, you get the "ding-ding" sound, the yellow warning triangle (or maybe its a big yellow exclamation mark), and the sat nav screen goes to the TPMS screen (I have Prof navigation). The TPMS shows all four tyres (tires) as being flat - colour of tire has changed from green to yellow - ie it doesn't identify which tire is flat. I suspect this is because it is the indirect TPMS and can only detect a relative difference in rotation between wheels - not which tire is at fault. I would have assumed the direct TPMS would indicate the actual flat tire.

I'm not surprised it takes a fair drop in tire pressure before the system alarms. Remember, the system is there to detect a failure of a run-flat tire which would usually mean a near total loss of air pressure. It would be at that point when the run-flat has deflated that you are then under the speed and distance limitations that apply for a deflated run-flat.

Tony

[Phoskins23]

Cadman - I had the same problem. I noticed you are in MA. I am in CT and it is getting colder as you know. Perhaps it is due to the colder weather. This has happened several times with seasonal changes on my volvo. I pumped all 4 tires from 26 to 35 psi and all has been fine since. My car is 3 months old.

[kozzi]

Originally Posted by Phoskins23

Cadman - I had the same problem. I noticed you are in MA. I am in CT and it is getting colder as you know. Perhaps it is due to the colder weather. This has happened several times with seasonal changes on my volvo. I pumped all 4 tires from 26 to 35 psi and all has been fine since. My car is 3 months old.

+1
I live in NY. Has happened to me every winter. Large temp drop and I get the "ding" on all 4 tires.

[vern]

The icon should come up between 4-7 lbs. drop in psi.
cheers
vern

[Jurisprudent]

I got a warning on all 4. Each was about 6-7 PSI below where it should have been (this happened when it turned cold, naturally).

[xDrive35i]

I believe it's +/- 25% of the PSI you set the TPMs at.

[alexg62]

Just happened to me in PA. Temps dropped to 32F and got TPMS warning. Checked the tire and it was down to 26.

[Tato97]

Temps drop here too and my car this morning had the TPM warning with pressures in 26-28 range.

[cadman50]

Mine hasn't gone off yet. I'll have to check them again to make sure the TPMS is working correctly. Thanks for the inputs.

[alexg62]

Yeah, mine were in 26 range as well. I was surprised that it dropped so much. This is my first TPMS car and I don't think I ever checked tire pressure in my prior cars as it got colder.