Can TPMS be recalibrated?

Looking at the front tire of the Volt yesterday, and it looked low. The dash indicator says all 4 tires were at 37psi, which is what's recommended. But it looked low, so i pull out my gauge (that I used for autocrossing, it's a pretty nice unit) and check it. 25 psi according to the gauge. Go around the car and all of them are saying 20-25psi. WTF? So I fill them to 36-37 psi all around. Now the TPMS is giving a warning that the tires are at 49 psi!

I trust my gauge, as I've been using it for years, and it seems to be accurate on the MINI with it's TPMS system, showing the tires on it to be at 35psi, just like the car is telling me. I'm wondering if the TPMS in the Volt can be recalibrated to match real pressures... Guess I'll have to call teh dealer (though they know very little about the Volt...)

Seems extremely unlikely that all four TPM are off the same amount, my first instinct is that your gauge is not as accurate as you think. Although if it does match the TPMS display on another vehicle that might show that it is ok.

The other possibility is that something in the ECU is interpreting the data string from the TPM incorrectly, but that seems unlikely as well.

Slightly off topic, but I'm quite heavily involved in tire and wheel assembly for Volt. If you PM me your VIN I can look up the tire build data.

+1.

TPMS are often off by 1-3psi but all four being consistently 20%+ off seems fishy.

In reply to Knurled:

it does. But the gauge seems to be accurate on the MINI, and when I use another cheap gauge, it echoes the good gauge within a couple PSI on both cars. My travel trailer came with 45psi in it, according to the gauge at the RV dealer, and my good gauge matches that, so when the one tire that has a slow leak in it goes down visibly, I use that gauge to set it to 45 psi.

Which is why I find it so wierd that the TPMS in the Volt is telling me it's that far off.

Now that I think about it, when I got the car in the winter, the TPMS indicated the left rear as being low (32 psi, vs 34-35 for the rest of them, and my gauge showed that to be the case when I went to fill it then (I put 35 psi in it by the gauge, and the dash showed it back at 35 psi afterwards).

I would be really interested to here what you have to say about living with a volt. It is the one Hybrid car I could see me getting.

In reply to dean1484:

Love it, actually. Commuting and errand running have been done on pure electricity, and not added any money to my monthly electric bill. At the same time, we took it on a 1500 mile road trip a couple weeks ago and got almost 60 mpg for the trip when the gas generator was used on the highway, and the electric was use around town.

The car is well built, solid and luxurious feeling (the silent rush of torque, all 280lb ft of it, helps contribute to that), and with a low CG, it seems to handle pretty god. It's fun to punch it from low speeds and feel that torque accelerate you. Lutz wanted it to be fun to drive, unlike a Prius.

A few things I wish about it: I wish it retained Sport mode setting when you shut it off, so that it didn't have to be selected in the menu every time you start the car. It would have been nice to incorporate solar cells on the roof to help power the fans to circulate air in the car when parked. Since it doesn't have that, it would have been nice to have a sunroof available... Also a heated steering wheel for the winter. I also wish that it would retain the charging rate setting when you shut it down. I know why they did it, but it'd be nice to have that stay put.