A tire pressure sensor is a small programmable electronic device that is located in the pressure pocket of a wheel and a tire and constantly measures the air pressure in the tire. The sensor transmits this information via low-frequency radio to the vehicle’s onboard computer and, if available, to a corresponding display in the instrument cluster.
It is displayed in pounds per square inch (psi) and has a yellow warning light on to warn you if one or more tires are short of air.
Tire pressure sensors are an essential part of the so-called tire pressure monitoring system (TPMS). Millions of these systems have been installed in passenger cars since the 2008 model year when they became mandatory in the United States.
Tire pressure sensors are typically attached to the valve stem assembly of each tire and are battery operated.
It Warns You That Your Tire Is Low
In the event that the sensor detects that the air pressure in a tire has dropped to a dangerously low level 25 percent below the recommended air pressure according to federal government regulations – a warning message or a light is displayed in the instrument cluster.
Tire pressure recommendations for the tires that were originally on a car can usually be found on a label on the sill of the driver’s door.
TPMS sensors are powered by batteries that are designed to last for several years but eventually lose their charge. Since the sensors cannot be easily removed when the battery is empty, the entire sensor must be replaced.
Replacement tire sensors vary in price depending on the vehicle and are available from many sources, from Amazon to Advance Auto Parts to Tire Rack or at your local tire store. Expect at least $ 100 for a set of 4 to be replaced at a repair shop or tire store.
You can continue to drive indefinitely with a failed TPMS sensor in one or more wheels, but then the system can never warn you if you have detected a puncture and are about to blow out.
There is a second type of tire pressure monitoring system that works completely differently. No tire pressure sensors are used in the tires, but the wheel speed sensors of the anti-lock braking system are used to determine if the speed of a particular tire does not match the others.
This indicates that the suspect tire has changed circumference and may have lost air pressure.
To ensure that your vehicle’s TPMS system pressure sensors stay on for as long as possible, always replace the valve stem cap after checking the air pressure or inflating the tires. This helps prevent corrosion of the valve stem, especially when salt is used to clear the roads in winter.
If the TPMS Warning Light Comes On
The purpose of the TPMS (Tire Pressure Monitoring System) is to warn you when the tire pressure is too low and may cause unsafe driving conditions. If the light is on, your tires may be underinflated, which can lead to excessive tire wear and possible tire damage.
It is important to understand the importance of properly inflating your tires and how TPMS can help you avoid a dangerous situation.
Both overfilling and underfilling can lead to premature tread wear and possible tire failure. Overinflation can lead to decreased traction, premature wear and tear, and the inability to absorb road impact. Overfilled tires show premature wear in the center of the tread.
On the other hand, underinflation leads to a sluggish tire reaction, reduced fuel consumption, excessive heat build-up, and tire overload. A tire with insufficient air pressure shows premature wear on both sides of the tread edges or “shoulders”.
If this is your first time learning about tire pressure sensors, finding the TPMS indicator on your dashboard is easy. It’s a horseshoe-shaped light with an exclamation point in the middle.
What Does A TPMS Warning Light Mean?
Do you know what to do when the TPMS low tire pressure icon illuminates? The first thing to do is to manually check your tire pressure with a pressure gauge and add air until the pressure reaches the vehicle manufacturer’s specification. (The correct pressure can be found on the driver’s door jamb or in the owner’s manual, not on the sidewall of the tire – this is the maximum tire pressure.)
Note that your TPMS is not a substitute for routine tire pressure maintenance. It’s a tool that can be used to get notified when the pressure is low. However, a tire can drop below the correct tire pressure long before the TPMS warning light comes on. The TPMS indicator lights up when the tire pressure becomes too low or too high.
- Tpms Light Illuminates While Driving: When the TPMS light comes on and stays on at least one of your tires is at a low pressure level. Check the pressure of all of the tires with a gauge and determine the cause of pressure loss and add air or service the tire(s) as appropriate.
- Tpms Light Goes On And Off: When tire pressure(s) are near the level that triggers an alert, fluctuating temperatures may be causing your TPMS light to turn on and off. This typically occurs when pressure decreases over night due to a drop in ambient temperature that causes the light to turn on; the light may turn off when pressure increases during the day due to rising ambient temperature and/or heat generated from the driving the vehicle. Use a gauge to check the pressure of all of the tires and add air to any tire that is low
- Tpms Light Flashes And Then Stays On: If the light flashes for approximately 60 to 90 seconds every time you start your car and then remains illuminated, this means the TPMS isn’t functioning properly and you should take it to an automotive service center for an inspection. Until repaired, the TPMS is out of order and is not able to warn you of low tire pressure. Check the air pressure of all of the tires with a gauge and add air to the tires that need it.
Does A Tpms Replace Regular Tire Pressure Checks?
No! Understanding what a TPMS warning light means and what to do when it comes on is an important part of the driver’s responsibility. However, it should not be a substitute for regular tire pressure checks. Why? Depending on the situation, the TPMS may have limitations such as:
- The TPMS warning light can be set to illuminate below the tire pressure required to carry the load in the vehicle.
- The sensors may not accurately transmit the tire pressure data to the on-board computer.
- The system may not be able to accurately determine if a tire is too low if other tires are depressurizing at the same speed.
Therefore, you should also use TPMS to check the tire pressure once a month and before a long journey or when carrying an additional load.