Tire pressure monitoring system means a system that detects when one or more of a vehicle's tires is significantly under-inflated and illuminates a low tire pressure warning telltale.Checked 2026-08-12
Tire Pressure Monitoring System (TPMS)
The system that detects significantly under-inflated tires and lights a dashboard telltale.
Also called: TPMS · tire pressure light
What it means
Definition
The federal standard defines a tire pressure monitoring system as a system that detects when one or more of a vehicle's tires is significantly under-inflated and illuminates a low tire pressure warning telltale. NHTSA describes the chain: information collected by the sensors is transmitted to an on-board processor that interprets the signals and warns the driver by illuminating the TPMS symbol. Direct systems read pressure from sensors inside the wheels; indirect systems infer it from wheel-speed data.
Why a buyer cares
What it changes
A telltale that stays lit after the tires are correctly inflated points at the system rather than the tires — a flat sensor battery, a damaged sensor, or sensors never relearned after a tire change.
In practice
Where you meet it
The horseshoe-shaped telltale on the cluster, and tire-shop invoices reading TPMS sensor or TPMS relearn.
Two things that look alike
Not the same as
The doorjamb placard lists the pressures the vehicle was designed for; TPMS is the system that watches them.
Read next
Related terms
Where this comes from
Sources
The information collected by the sensors is transmitted to an on-board processor that interprets the sensor signals and warns the driver when tire pressure is below the acceptable level by illuminating the TPMS symbol on your dashboard.Checked 2026-08-12