Do You Know What This Warning Light Means?

by Moderator on ‎09-14-2015 10:50 AM - last edited on ‎10-05-2015 10:56 AM by Lithium Technologies (5,189 Views)

It means one of your tires has dropped 25% below its optimal air pressure, potentially tripling your crash risk.


Your vehicle’s warning lights are critical to its health and your safety. A prime example of this is the light warning you that at least one of your tires is dangerously low on air and at risk of a blowout. Additionally, driving on one or more underinflated tires wears them down faster, reduces your vehicle’s gas mileage, and negatively impacts its handling, braking and load capacity. Fortunately, recent automobile technology can warn you when you’re driving with a tire low on air.


Tire Pressure Monitoring Systems

Since 2008, tire pressure monitoring systems (TPMS) have been required on all new cars and light trucks. To help prevent tire-related crashes, the TPMS triggers a warning light when a tire’s pressure falls 25 percent below the manufacturer’s specification. There are two types of TPMS:

  • Indirect systems, which use wheel speed sensors to infer tire pressure
  • Direct systems, which use air pressure sensors to monitor actual tire inflation

The Warning Light

Despite the presence of this warning light, a 2014 study by Schrader (a major supplier of tire valves and pressure sensors) found more than 40 percent of drivers could not identify their vehicle’s TPMS alert symbol. Even among those who could identify the alert symbol, 10 percent said they have ignored it and continued driving, and 21 percent said they would continue on until they had an opportunity to visually check the tires for underinflation. Unfortunately, a tire is not visibly underinflated until it is at least 50 percent low on air — which is dangerously low.


Check Tires Monthly

All tires gradually leak air over time, so whether your vehicle is equipped with a TPMS or not, it is important to inspect its tires at least once a month. Look them over for wear and damage, and check their inflation with a quality tire pressure gauge. If your car is equipped with a TPMS that can display tire pressures on the dash, this task will be easier, but you still need to visually inspect them.


To be certain your tires are inflated to the manufacturer’s recommendation, check your vehicle owner’s manual or the placard attached to the vehicle door edge, doorpost, glove box door or fuel door. Never inflate tires to the pressure stamped on side of tire—that number is the maximum pressure the tire can withstand.


To be certain your vehicle’s tires are in good condition and properly inflated, have them checked by a certified technician. At AAA Approved Auto Repair facilities, AAA Members receive a free 24-point inspection that includes tires among the components checked.


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by KarKnut
on ‎10-07-2015 07:46 PM

The problem, like a lot of other sensors in modern cars,  they throw off erroneous warnings - and thus create general malaise among drivers. Rapid ambient temperature changes - like say your nice warm garage out into the winter snow, will cause these pressure warning lights to come on when there's no issue at all. You can't legislate intelligence or common sense. People need to realize they are driving a 2-ton missle and need to take more responsibiliy for taking care of their vehicles. Checking oil levels, coolant levels, brake fluid leves and tire pressures used to be part of every motorists ritual. Now most people don't do any of those things, and have no idea of the importance of any of them.

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