Took my son to college orientation a couple of days ago. He will be a freshman at Appalachian State in Boone, NC. We live about 2 hours away from Boone. We got their on Sunday. Monday morning, we got in the TCH and the TPMS light came on. I had just gotten new tires last week and figured they screwed up the sensors. Well, today we left Boone and about an hour out of town, the light went off. So I'm guessing a change in altitude affects the tire pressure?

 

Cooler temps will lower the pressure in the tires. The tire shop probably put the pressure on the low side of what the sensors are set for. Re-check the pressure with the tires cold (best if they sit overnight).

 

Went back to tire store and had pressure and sensors checked. They said everything looked normal. Light went off later that day and hasn't come back on yet.

 

The instruction manual for the TCH lead me to a button just to the left inside of the glove box. It mentions if you change the air pressure in your tired, to press that button for a few seconds. I forget the details other than that. Might be a good idea to do this with the new tires. It must set the receiver to detect the new pressure and then make it the default.

 

If I recall right, the TPMS light comes on when any tire, including the spare, drops pressure more than 25% of the "set" pressure. If your spare is low, it could be causing the TMPS light to come on when cold. My spare drops about 10 PSI ever two months. I top it off about once a month when washing the car.

I run my tires at 40PSI, but inflate my tires to 45 PSI when I set the TPMS system. If my tires drop 25% (under 35PSI), the TPMS light comes on. I picked up a hunk of steel this weekend in a rear tire. It was 1/8 by 3/8 and about 5 inches long. My TPMS light came on and I was able to take the next exit, after 3 miles, and pull into a gas station. The tire was down to 20psi. It was unrepairable as the steel had gouged out some of the sidewall.

 

If the spare had not been used, this sounds to me like a leaky defective tire from the factory. Would that be a warranty issue. I don't recall ever adding any air to my '94 Corolla, 185,000 miles and the spare still had high inflation when I sold it.

 

Light hasn't come on in the past week so I'm guessing a tire was a little low on pressure when they mounted the new ones. Will check the spare just in case.