When your tire light comes on, what should you do?

Driving on underinflated tires are one of the number one reasons for catastrophic tire failure. To help avoid this, it is critical to perform a visual inspection of your tires at least once a week and check your air pressure once a month. In the interim, all vehicles manufactured and sold in the United States after September of 2007 are required to have a suitable tire pressure monitoring system (TPMS) sensors. TPMS sensors are designed to alert drivers when one ore multiple tires are drop below 75% of their recommended cold tire pressure. So, what do you do when the tire light comes on?

Determine why the light came on. 

  • A punctured tire 
  • Natural loss of air pressure. Tires will naturally lose about 1psi/month
  • Cold weather (On average, every time the air temperature drops 10 degrees Fahrenheit, the tire will lose about 1 psi.) Do note, if your tire pressure light comes on during a cold morning, as the head raises, the light may come off automatically.

To do so, first, do a visual scan to determine if one tire is significantly punctured and therefore significantly underinflated. After this, check your tire pressure with a gauge. (In case you do not know the recommended psi for your vehicle, you can locate this information on the placard in the driver-side door or in the user manual.) After assessing the tire pressure, if you discover one tire is more underinflated than another, I suggest looking more closely at the tire to see if a nail is causing a very slow leak. 

If any of your tires are below the specified pressure, go to the nearest gas station with an air pump and fill the tires.

This is an closeup view of a dashboard showcasing a tire warning light

Photo Credit: DCH Paramus Honda

What happens if the light comes on but the tires are properly inflated?

Once you have confirmed that all of your tires are indeed at the correct air pressure and the light is still on, your TPMS sensors may be malfunctioning and they need to be replaced. Fortunately, we help with this! Give us a call at 919.636.3338, and schedule your appointment.

How do TPMS sensors work?

There are two types of TPMS sensors that comply with the Department of Transporation’s regulations: direct tire pressure monitoring system, and indirect tire pressure monitoring system.

Indirect TPMS Sensors

This is an info graphic produced by Bridgestone explaining how a direct TPMS sensor works

Photo Credit: Bridgestone Tires

An indirect TPMS sensor measures the revolution rate of each tire. When all four tires are filled at the same psi, their circumference will almost be the same, thus the revolution rate will be very close. If one or more tires lose air pressure, the circumference will decrease, and those wheels will have to spin at a faster rate to travel the same distance as the properly filled tires. When a rate changes, the warning light will come on. 

That being said, indirect TPMS sensors are not measuring the actual tire pressure, and will not provide psi readings like a gauge can provide.

Direct TPMS Sensors

A direct TPMS sensor measures the actual pressure of each tire (and temperature rating). When the tire pressure drops 25% or more beyond the required psi, this will signal the warning system via Bluetooth. 

As stated by Bridgestone, “Many manufacturers use proprietary technology for these highly specialized systems, so replacing a TPMS in a way that’s consistent and compatible with your vehicle will require an experienced, knowledgeable technician.”

Which TPMS sensor is best?

Is one better than the other? Not necessarily, there are pros and cons to both options. But neither one of these can or should replace a weekly visual inspection and monthly tire pressure check. Ultimately, they can fail. 


  • Indirect TPMS are less expensive
  • Direct TPMS are more expensive


  • Indirect TPMS are less accurate as they not measuring the actual tire pressure. In addition:
    • Installing different tires can impact the reading
    • If a tire is worn unevenly, this can also impact the reading
  • Direct TPMS: more accurate as it measures the actual tire pressure. 


  • As for indirect TPMS, they require less overall maintenance and repair. However, they need to be reset every time tire pressure is filled and tires are rotated.
  • Direct TPMS, they are simple to resync after tires are rotated or replaced. Also, the batteries will usually last for about ten years, however when the battery is drained the entire sensor needs to be replaced. Sensors can also get damaged during mounting and dismounting. 



So, when your tire pressure warning system alerts you, you definitely need to address it! But just note, this is more of a warning and/or a reminder to check your tires and their pressure. If you have any additional questions, please contact us at 919.636.3338!

If you need new tires, click here to request a quote!