RE: First flat tire...rear sidewall cut. Testing tire sealant now....
I had the same problem-- TPMS light went off but the diagnostics screen showed crazy high pressures (56 psi front and 49 psi rear!). Of course when I measured them they were fine (40 fronts 36 rears). I took the car to the dealership and they recalibrated the TPMS sensors (or how the TPMS data is interpreted?) So far so good.