OEM TPMS and high pressures
just got my 2008 HCH II back from the tire shop, having had them swapped over my winter tires/wheels to my 3-season tires/wheels (both OEM, with OEM TPMS installed). When I first drove home, the TPMS system seemed to behave ok (no warning lights, and the shop usually does things right). Then the next day, I pulled a classic rookie error, brought the tire pressures up from 36 psi to 42 psi (with air, not Nitro, and while the car and tires were cold), feeling groovy about my anticipated mileage. However, we're having a local heat wave, and about half way through my errands around town, the TPMS light came on. I stopped right away, found none of the tires low; rather, the pressures were up around 49-50 psi. Oops. I tried dropping the pressures back to 38 psi (cold) but the TPMS dash warning light remains lit.
I checked my manual, which states that the OEM TPMS system should not respond to overly high pressures-- but is this correct? I know some of the aftermarket TPMS systems detect both low and high pressures. If the warning light was NOT activated by the high pressures, is this most likely due to an error by the tire shop when installing the summer wheels? It seems odd that the warning light did not light up until the following day.