Wow! TPM really works.

[fpage77]

My TPM went off this week and my right rear time was low somewhere under 30 psi but can't remember the exact number. I pumped it up to 36.4 psi and then reset the TPM. I was out earlier doing errands and the thing went off again and my first response was the dumb car is messing up. I was blaming the car itself thinking like with my check engine light and gas guage mess that this was false information. I started checking back rear tire and it was down to about 25 psi but this time I saw a nail right on the top edge between sidewall and thread. I was at my local station and they patched it and I checked pressure on all four of my tires and filled the right rear again. I've reset the TPM again but gee I didn't know I even had a nail if I didn't have TPM.

[SunDiego]

Glad to hear it helped you!

[burtandnancy]

I didn't like the ride of my smart, thought the tire pressures too high for the quality of the local roads, so lowered all four tires. Bingo, set off the alarms, but after resetting everything fine. Nice feature...

[fortow]

There's no need to reset (recalibrate) the TPM unless you use install tires with new TPM monitors, rotate the tires (if possible), or want to change the pressure readings that are measured.
If you do press the TPMS button on the dash, make sure that the tires have been filled to the proper cold pressure. Only press the button when the tires are cold and at the correct pressures.

If the telltale display indicates a low pressure you need to determine the tire or tires that are low. Once the pressures are brought back to the proper setting the display will no longer display the telltale.

The indicator on my display was showing after the weather turned very cold. Simply reinflating to proper pressure removed the telltale.

One of my another vehicles actually displays the exact pressures in each individual tire. That is a far better system - no guessing what has happened or which tire is low and it can indicate a slowly leaking tire before it becomes a problem.
These systems have been implemented because people ignorantly drive on tires with very low pressures. This at least directs their attention to a problem that would be ignored otherwise.

[SuperGeek]

Yes, the TPMS is a great feature. One thing to remember is it's not an instant read. It will not alert in the case of a blowout or sudden flat. It takes an average over like 15 minutes (read the manual for specifics). So even adding air may not cause the light to go off instantly; it may take a few minutes of driving before it confirms all is well. I think shutting off the engine before filling may cause it to re-test, but I'm not sure.

Like fortow suggests, it's important to realize the TPMS is like the gas gauge - it's not an exact indication, and requires intelligent action or analysis from the driver. Keep a digital tire gauge (forget analog, spend an extra 10 bucks once every 10 years) and measure weekly, monthly, whenever you suspect a problem. Then cap the valves - uncapped valves are the most common source of very slow leaks.