Cars Built Since 2008 Have Tire Pressure Warning Lights
By Chad Upton | Editor
Last week, I was driving behind a car with a tire that was nearly flat. The tire was so low, it was almost riding on the rims.
At the next red light, I waved at the driver and they opened their window. They put their cell phone down while I told them about the tire. They were surprised, thanked me and went back to talking on their phone. Even though there was a service station across the street, where they could have easily added air or at least checked the tire, they drove off like nothing was wrong.
I was shocked.
Apparently, some people don’t understand how dangerous a flat tire can be, not to mention the poor gas mileage and possible damage to your wheel. In fact, it’s not just this person. 33% of drivers don’t know what the tire pressure monitoring system (TPMS) warning light is when it lights up on their dashboard.
Since 2008, all cars in the US are required to have a tire pressure monitoring system. Many cars, especially luxury cars and SUVs, have had them for longer, but the importance of these systems became clear during the Bridgestone/Firestone Tire debacle in the year 2000. Some sources report there may have been as many as 250 deaths and 3000 catastrophic injuries from under-inflated tires and that tire pressure monitoring systems could have saved lives and reduced injuries.
The tire pressure monitoring system will illuminate an icon on your instrument cluster when the pressure in any tire drops more than 25% below the recommended inflation level. The icon is a cross section of a bulging tire with an exclamation point inside of it.
Some cars have more advanced systems that will identify which tire is under-inflated. The more advanced systems can also tell you if a tire is over-inflated and when it is just a warning that can be addressed soon or if it is an emergency that requires immediate attention.
As the seasons change and the weather gets warmer or cooler, tire pressure changes too — that’s a good time to pay extra attention to tire pressure. If your vehicle warns you of a tire pressure problem, you should pull over to check the tires. This could really be a life saver, especially if you’re driving at highway speeds when the light comes on.
Whether you have this light or not, you should check your tire pressure regularly, and especially if they’re bulging. Most service stations have an air compressor to fill your tires, many of these are equipped with a pressure gauge that you can use without turning on the compressor (which costs money in some cases). Otherwise, the service station may be able to lend you a gauge.
On the inside of the driver’s door frame, there is usually a sticker that indicates the proper tire pressure for your vehicle. If not, check your manual.
Your manual will also tell you how to calibrate the tire pressure monitoring system. If your system is capable of telling you which tire is improperly inflated and you check the pressure in that tire, only to find that it is perfect, then your tires were probably rotated without calibrating the system to match the new tire locations.
Some systems use wireless sensors on each wheel, these are known as direct measurement systems and they are more expensive. The other main type of system relies on the ABS sensors to determine that one wheel is turning at a slightly different speed, indicating it is low. This system is cheaper, but it only works when the vehicle is in motion.