03 JGC: Tire Pressure Sensor "BAD/MISSING"????

Does anyone know how to reset this error message or make it go away?

I went in for an oil change and on start up from the dealer to leave,
this error message came up. Yes, I know they fk'd it up. I disregarded
it at first as I thought they rotated my tires & did not retrain the
sensors. But they did not rotate the tires and this damn error message
won't go away! I changed the tire pressures in all 4 and retrained the
sensor. It all registered correctly but on boot up, the self-test spits
out this "TIRE PRESSURE SENSOR BAD/MISSING" error message.

The service rep had the audacity to tell me it is because my spare tire
was missing the sensor - I told him I have a 4-sensor system & my spare
tire does not have a sensor. He said he does not understand why for 80k
miles I have not had this happen.

The new sensor is $88, the labor is $26. I think I am being ripped.

Can any of you guys/gals help out? It's driving me nuts. This is my 4th
JGC and I have NEVER seen this. Have had the car for 80k wonderful miles
and going very strong. This has never happen before.

Any feedback will be much appreciated.

Thanks all