GMC TPMS Packet Structure

[Joshua Gillis]

I am currently playing around with a Pluto radio and my GMC vehicle. I have received the tpms data and decoded it from manchester to have the correct bits (I have identified the TMPS sensor ID within the structure. I am unable to decode the rest of the Packet. Does anyone already know the packet structure/how to decode the bytes for a GMC vehicle? Any help would be appreciated. 

[Christian Z.]

A good approach is to record data codes over a period with slowly changing conditions. Maybe do a short drive with a cold tire. You should see the pressure (and perhaps temperature) increasing in some bits.

[Greg Troxel]

And, I would add: I think it's perfectly ok to write a driver that
decodes the id, perhaps badly, and puts the rest of the bits in unknown1
to unknownN and then to improve it. We are all in a vague sense
cooperating on everything, and the more partial work we have captured,
the easier it is for the next person.

As an example, when I came to rtl_433, there was a Ford TPMS decoder,
but I figured out more about it and improved the driver, definitely
pressure representation and I think a 'moving' bit, but the details have
left my head. I left them in comments though.