What is TPMS and why does it matter?

What is TPMS sensor/light explanation

Have you ever started your car to see this () little symbol light up on your dashboard? I know that lots of us have and for the majority of drivers, they aren’t even sure what it means, but it is actually a crucially important system that alerts a driver that one of their tires is flat or underinflated. However, a study by Schrader International, found that 42 percent of drivers are unable to identify the low-tire-pressure warning light on their dashboard. Roughly the same percentage of those polled admitted to rarely checking the tire pressure. This leads us to the question if people aren’t able to identify the light, they probably do not know that it’s alerting them to a potentially serious safety issue.

NHTSA estimates one-in-four cars have at least one significantly underinflated tire and driving on underinflated tires increases a drivers chance of being in a serious accident by 300%!

The little warning light is the alert from your tire pressure monitoring system (TPMS) and it is telling you to check your tire pressure but depending on the make and model of your car, the system will not tell you which tire is underinflated, by how much, or for how long.

By law, any car manufactured for the US after 2007 has to have a basic TPMS installed. This type of TPMS is known as an indirect TPMS. 

Indirect TPMS use a vehicle's anti-lock braking system's wheel speed sensors to compare the rotational speed of one tire versus the others. If a tire is low on pressure, it will roll at a different number of revolutions per mile than the other three and alert the vehicle's on-board computer. Indirect systems are unable to generate accurate readings in cases where all four tires are losing pressure at the same rate, such as the effects of time and temperature. They are also unable to detect slow leaks. This means a driver is likely only alerted when the tire is flat, leaving a driver no other option than to change the tire or call a roadside assistance company to change it for them.

The other TPMS on the market is known as direct TPMS, which is more common in luxury vehicles and rarely comes standard, attaches a pressure sensor/transmitter to the vehicle's wheels. An in-vehicle receiver warns the driver if the pressure in any tire falls below a predetermined level. Direct systems are typically more accurate and reliable and most are able to indicate which tire is under-inflated but it still may not tell you exactly what the problem is.

At nonda, we understand that tire pressure is a huge safety issue that drivers often do not think about until it’s too late. That is why we will be launching an app-enabled Smart Tire Safety Monitor in the coming months. You can find out more about our smart tire safety device here.