I've noticed that it seems like Tire Pressure monitor was available on the 04 'burbs, and I read a post about someone with an 04.5 Duramax getting a "service tire warning" message in his truck. Would it be possible to add factory TPM to our trucks?

Just curious...

Im sure it would work, but I dont know if it could be calibrated to the higher tire pressures we run.

IIRC TPM was only availible on 05+ SUV's. I think in 2005 when it first started, it would only say "tire pressure low", and in 2006 they actually started showing psi in the DIC.

Finally, im not sure if our clusters support it...2005+ dmax's might but Im pretty sure 2004 and earlier would not.

it's an option in my 2004 GMC that I stumbled on when drilling down through menus with a tech 2, think it had something about calibration or set points, don't remember exactly