When I had gotten my, new to me 2006 T4R, I had a dead TPMS sensor in the spare that did not trigger a TPMS light.
I have since gotten all 5 sensors communicating.
When I drive around without my spare tire, I don't get a TPMS sensor light on. I have done that for weeks at a time. When I plan to stay local, I leave the spare tire at home, cuts down on 50+ lbs.
I don't know if the TPMS can work with just 4 sensor IDs uploaded to ECM, instead of 5 sensor IDs.