How to reset air sensors?

Here's what the problem was.A few months ago,I got new tires on the rear and they put the rear tires on the front.So the front was low.I went back to the owners manual and reset the tires.Thanks for the help.

In your owners manual there should be a section on "Relearning" the tire pressure moniters. Look in the index. It involves selecting relearn on the instrument panel and then starting in a certain wheel position and adding air or letting air out until the horn beeps, and then quickly go to the next wheel and do the same thing until the horn beeps, and soon until you do all 4 wheels. You need to follow the sequence spelled out in the manual so the sensors will "relearn" each sensors correct position so when it says Left Rear low, it means Left Rear and not right rear or some other position because someone did not "relearn" after rotating wheels or some other repair. And usually the spare tire does not have a sensor so if you put the spare on it will not read that wheel position. So look in the manual index and see what you find. It might be in the index under the heading of "Tires". Here is a sample of what it might read.TPMS Directions

This warning drove us crazy in my wife's 2008 Pontiac G6. The pressure was set to the tire maximum, and every once in a while it would say low pressure and wouldn't go off. Then, it started saying we had a defective airbag sensor. Then other items started giving warnings. To make a long story short, it wound up being the car battery!

One day it wouldn't start. So we put in a new battery and all the warning lights went off and never came back. I mentioned the problems I had been having to my GM service manager, and before I could even tell him about the battery, he said "did you replace the battery?" Evidently, the GM vehicles are very sensitive to having the proper battery voltage.

This may or may not be your issue, but I'd sure check on the battery especially if it's a two year old original GM battery. That's about how long they last.

Be sure its warning you of the correct tire. If they have been rotated and not reset you will be getting false info on the actual tire thats low.

Sometimes you have to drive it for a few miles before it will register....

What pressure was the van saying the tire was at before you put air in? What about after? I can run my tires as low as 65PSI and I don't get any warning in the DIC. Or was it a general TPMS warning and not low pressure?

Study your owners manual some more, there should be a way for it to relearn. Usually a couple of start/stop cycles will do it. You need to check all your tires for proper air pressure, just to be safe.