Tire pressure sensors

I'm trying to find help on the TPMS. Today when I started my truck there was a "check left front tire" message . I went through the info center and it showed the correct tire pressure. I checked it manualy also. pressure OK.
Since it was time to rotate the tires anyway, we did. The tire "place" followed the instructions "to the letter" and cannot get past the driver's front tire. Now if you have to follow the correct order, if the sensor is bad in the left front, how on earth do you find out if that is the problem?One of the many times we tried going up and down with the pressure, the left front finally "chirped" but then the "SERVICE TIRE  MONITOR SYSTEM" error appeared.
HELP!

i the DIC you there is a function to 'relearn tire position' or something like that....I dont really know, not much experience with the TPMS, but seems to be a headache for everyone....try relearning in hte DIC and see if tht helps...