Okay, this is on my pastor's mini-van but I know the newer 4runners have this warning light too.

One of the tires on the minivan blew out a few months ago and, of course, the warning light activated. He decided to play it safe and had all of the tires replaced. Just a few minutes after he drove away from the tire place the warning light popped back on. He checked the pressure on all 5 tires (spare) and they're all good.

Anyone know what could be wrong?
Can you clear the light by disconnecting the battery or pulling out the EFI fuse?

 

Um, what year minivan (assuming your talking about the Sienna). They have an indirect tire monitoring system. Anytime tires are replaced, rotated, tire pressure changes it is recommended to reset the system. There should be a button with a similar picture to the warning light on the combo meter. Press and hold till the light flashes a few times and goes off. The new 4Runners, etc have a direct tire pressure warning system, meaning all five tires are monitored through a special valve stem that transmitts signals to the ecm. The one the Sienna has just works off rotational speed of the four tires that are in contact with the ground. The new Tundras and Sequoias have the direct system with a reset button... technology, are cars are smarter than us

 

Ive also heard the sensors (on other brands) have an alarming failer rate and dealers have all but stopped replaceing them because its time consumeing.