2012 K1600 TPMS reading 7-8psi too low

[e7navy1999]

Tire pressure is at 40-41psi verified by three gauges.  Front wheel is ok at 40psi.  Rear TPMS shows 33psi.  How can I calibrate this rear TPMS to read the correct pressure?  I did the ...let all the air out of the tire quickly and the TPMS does respond with the red triangle on the dash as well as the engine going into limp mode.  I refilled to 41psi and the Rear TPMS shos 33-35psi ...sort of sticks on those numbers. 

[e7navy1999]

What I decided to do is order in two new TPMS sensors from China for $22 bucks free freight and put in fresh battery with 4in leads so in the future I can solder in new batteries in a few seconds.  I will let you all know how it goes.  I already have the GS911 and I purchased on amazon the EL-50448 as per the help from this site.  Should know in a few weeks after everything comes in the mail.  My next tire change is about October anyway

[GS Jim]

Are you checking on a cold tire, the dash readings should be temperature compensated so if it is really hot you would get a large difference in gauge and dash readings but 8 psi does seem a bit extreme. When you get your wake up tool you should also be able to get actual and compensated readings on live values with the GS 911.

[e7navy1999]

Hey Jim Thanks.  Does the GS911 allow me to calibrate the TPMS back to the actual gauged tire pressure or am I just going to be able to read the pressures? 

[GS Jim]

I have never seen any way to calibrate them, it would be done originally. Did it read properly at one time and then go wonky because if so then it probably is toast.

[e7navy1999]

Thanks Jim, Yes it was always within 1 PSI since 2012.  Now it bugs me becasue i have to check my tire pressure before each ride.  8psi off is scary to me especially since I ride a little on the over 80-90mph side of life.