Does the tire pressure monitoring system reset itself upon pressure correction or does the dealer have to reset it?

Resets itself.

generally after a short drive the sensors send the correct signal to the TPMS module and the light goes out.

Resets itself.

Damn grapes....youre quick!! Beat me to it.

- Irish :cool:

Here's a weird one...I'm pretty sure the TPMS works by sensing differences in wheel speeds, right? Mine illuminated yesterday morning right after starting the engine, before even getting the car out of neutral. Topped 'em all off, and it went out - again before moving anywhere. Odd, no?

Only the Navi uses the TPMS sensors as they rotate for the map matching function.

The actual pressure reading is transmitted at all times

The TPMS transmit actual pressure at a set interval; they also have nothing to do with the navigation system... The navigation system determines distance and direction when out of satellite view using input from the ECU, speed and steering angle...