I'm surprised to not see any mention of indirect TPMS anywhere in these comments. https://en.wikipedia.org/wiki/Tire-pressure_monitoring_system#Indirect_TPMS h

I'm surprised to not see any mention of indirect TPMS anywhere in these comments. https://en.wikipedia.org/wiki/Tire-pressure_monitoring_system#Indirect_TPMS https://en.wikipedia.org/wiki/Tire-pressure_monitoring_syste... It has its own shortcomings, but in my opinion they're all relatively minor and it does the job of warning the driver of potential pressure problems without wireless or in-tire sensors that require replacement. EDIT, never mind, I wasn't seeing "indirect" in the comments but now that I look I do see "ABS", which is what iTPMS depends on for determining wheel speed.