Tire Pressure Monitoring System Sucks

[chimchim]

I'm pretty disappointed in the tire pressure monitoring system. It worked once to alert us that we got a nail in a tire once. I realize it will not tell you when you are just 2-3 psi low. However, we recently got a slow leak, and the tire worked it's way down to 19 psi (from 30 psi normal). If the system can't detect this, what's the point?

I understand how it works: differential in speed between the tires. It is recalibrated every time you start the car; which means slow leaks are not detectable unless there is a threshold that says something is just wrong once the ration of rotation between tires exceeds a certain level.

[RX in NC]

Checking your tire pressure yourself on a weekly basis is still and always will be the best and fastest way to detect problems with your tires. You'll notice slow leaks sooner and therefore you'll be able to find and fix nails in your tires before they are able to cause significant damage.

[Booyah]

I can see where it may not alert you to 2-3psi because of fluctuation in pressure from day-to-day driving!

But you are saying it never alerted you and your tire was down to 19psi? That should not have happened

[RXinMN]

When we bought our RX330 a few months ago the salesman actually didn't recommend the tire pressure monitoring system. He said that they're prone to false alarms, especially when you garage the vehicle and then drive it outside where there's a significant difference in temperature. Apparently, a change of a few degrees is enough to trigger the alarm.

I can only assume that if it's a gradual change over time it will not trigger. Sounds like a design flaw to me...

[indiasfinest]

the change of temperature causes faulse alarms because heated molecules travel a lot faster...thus increasing tire pressure and vice versa....the instruction manual also says that you should not rely solely on the tire pressure monitering system

[chimchim]

But you are saying it never alerted you and your tire was down to 19psi?  That should not have happened

←

Yup. My other tires were about 29 psi, and the low tire was 19 psi; a 10 psi difference and the warning light did not go on.

[thdoan]

I'm pretty disappointed in the tire pressure monitoring system. It worked once to alert us that we got a nail in a tire once. I realize it will not tell you when you are just 2-3 psi low. However, we recently got a slow leak, and the tire worked it's way down to 19 psi (from 30 psi normal). If the system can't detect this, what's the point?

I understand how it works: differential in speed between the tires. It is recalibrated every time you start the car; which means slow leaks are not detectable unless there is a threshold that says something is just wrong once the ration of rotation between tires exceeds a certain level.

←

The Toyota tire presuure monitoring system recalibrates when you press the button under the steering column. And one should recalibrate this system only after tire rotation, tire change for instance.

Once on my 2000 Sienna, after tire rotation, the garage did not reset my system, and the indicator sure goes on. Another time, it goes on, and sure I do have a flat tire.

Another time, my RX330 loaner tire pressure lights up, and yes I found a low pressure tire. I did not check to see how much PSI I had left.

For sure, such system can not tell you if you have few PSI different. But I feel that it works fine for me.

[chimchim]

The Toyota tire presuure monitoring system recalibrates when you press the button under the steering column. And one should recalibrate this system only after tire rotation, tire change for instance.

Once on my 2000 Sienna, after tire rotation, the garage did not reset my system, and the indicator sure goes on. Another time, it goes on, and sure I do have a flat tire.

Another time, my RX330 loaner tire pressure lights up, and yes I found a low pressure tire. I did not check to see how much PSI I had left.

For sure, such system can not tell you if you have few PSI different. But I feel that it works fine for me. 

←

Yeah but the problem was that it didn't catch my 19 psi tire. My routine check discovered it and as a response to MY routine checks I patched the tire.

The only possibility is if the last rotation (which was done by a Lexus dealer) did not reset the the system.

[stonecutter]

If the car recalibrates every time you start the car, as you say, then Lexus places the burden on you to make sure the tires are alright at the beginning of every trip. The monitoring system only detects differences in tire pressure that occured during the drive (bad English, but you get the point).

The tire pressure monitoring system is not meant to replace routine tire maintenance, it is a safety feature designed to alert you of an impending hazard. A fast leak would be a driving harzard, a slow leak would not.

[thdoan]

If the car recalibrates every time you start the car, as you say, then Lexus places the burden on you to make sure the tires are alright at the beginning of every trip. The monitoring system only detects differences in tire pressure that occured during the drive (bad English, but you get the point).

The tire pressure monitoring system is not meant to replace routine tire maintenance, it is a safety feature designed to alert you of an impending hazard. A fast leak would be a driving harzard, a slow leak would not.

←

No, the system recalibrates only when you told it to (by pressing the button under the steering column). ;)

[agerickson]

Bah! - I apparently had picked up a nail that deflated my driver's front tire totally overnight in my garage.

I didn't figure out what the odd noise was until I had travelled 3 block in my neighborhood. The tire monitor system NEVER CAME ON!

As a result - it cost me $$$ for a new tire from the dealer, and a lecture on how the tire monitor system recalibrates on starting.

Thanks for nothing LEXUS!!!