So the other day the little (!) light on the dash comes on, the truck "dings" at me, and a little message comes up... "Tire Pressure Low"...

I check them, and sure enough, one is at about 28psi or so. I figure what ever, no big deal; a cold front pushed through, so maybe the cool air played with the tire pressure.

So I filled it back up, and evened them all out to 35psi all the way around.

I then hop in the truck to drive to the store, and the light is still on; stays on all the way to the store, the hole time me KNOWING that all of the tires are fully inflated. When I got to the store, I pulled the manual out of the glove box and looked up the TPMS. After some reading, I found that it said "it may take up to 20 minutes of driving above 30mph before the light turns off", so I figure it'll turn off after some driving...

3 days later, it's still on


I took it to the local dealership today and had them look at it. The service tech drove it around to the bays, I mumbled over the oogled at a Raptor for a little bit and they pulled the truck back around within about 5 minutes The service tech hops out, and says "all done, just had to recalibrate them"


...



so does this mean that every time one of my tires goes low for whatever reason, I'll have to go by the damn dealership to have the light turned off?

 

no, you shouldn't! the light should have turned off after a little driving. had this happen in my Fusion before i traded it for my truck. one tire was down to 25lbs, filled all of them back to 35lbs and the light went off after about 5-6 miles. not sure what happened on your truck? but THAT shouldn't have happened at all.

 

When the TPMS system generates a low pressure warning, it latches the event, logs it and lights the light. When you fill the tires and the pressure is above the low warning level, the TPMS should identify the new condition, turn off the light and unlatch the warning.

If the light does not go off following a couple of key cycles (power off with the door open or time out) then there may be a problem. You can pull the ground on the battery and wait for 15 minutes to reset the computers and the light should be out upon rebooting the computers.

If the light does not go out, it may be because the TPMS is not linked with all 4 sensor / transmitters and that would require a resync of the sensors in the tires to the receiver in the truck.

 

Or you have an 09 with bad sensors like I did. Changed 3 in the one year of ownership.
No problems with the '10 so far.