Tires that have been left over-inflated or under-inflated for a long time can wear out rapidly, and in some cases, even blow out altogether, leaving you stranded in the middle of the road.
So if you’re researching ways in which vehicles monitor and keep track of the inflation pressure, you may be wondering: what is a tire sensor? If you’d like to find out, keep reading to see what I learned!
What Is A Tire Sensor?
A tire sensor monitors the inflation pressure of a vehicle’s tires and notifies the driver when it is out of range. Direct tire sensors work by measuring the inflation pressure directly, whereas indirect sensors compare the rate of revolution of the tires to determine any imbalances.
If you want to learn more about types of tire sensors, their working mechanism, things that damage tire sensors and more, keep on reading!
How Many Types of Tire Sensors Are There?
You will usually find two types of tire sensors available with various automotive retailers – direct and indirect tire sensors.
Although both types have a similar purpose (i.e. to indicate when the inflation pressure goes out of range), they work differently and offer different advantages.
How Does A Direct Tire Sensor Work?
Direct tire sensors continuously monitor and track the inflation pressure of a tire and are installed in the inner side of the rim.
A complete tire pressure monitoring system would consist of an indicator in the vehicle’s dashboard and four direct sensors (one sensor per tire).
Direct sensors are manufactured in two distinct configurations, the first being a high line system in which low-frequency transmitters are used and the vehicle requests data from each sensor periodically.
In this case, the sensors are switched on only when the vehicle requests data, preserving the battery. Additionally, each transmitter sends data one after another in a coordinated manner.
The second type of sensor is a low line system in which transmitters send data to the vehicle indicator independently at set intervals.
Since the information sent by these sensors is not coordinated, it is possible for the messages from the tires to interfere, making it difficult to interpret the data.
To overcome such issues, the transmitters send data more frequently to make up for any missed readings.
How Does An Indirect Tire Sensor Work?
Instead of directly monitoring the inflation pressure in tires, indirect tire sensors rely on the vehicle’s Anti-lock Braking System (ABS).
The ABS measures the speed at which the wheels are rotating, and is able to identify when all of them are not rotating at the same rate.
If a tire does not have proper inflation pressure, i.e. is over-inflated or under-inflated, its rate of revelation becomes different from that of the other tires.
When this happens, ABS sends a signal to the vehicle’s central control system which switches on the low inflation pressure indicator in the vehicle’s dashboard.
However, keep in mind that indirect sensors are cheaper than direct sensors because they do not require any additional components (other than the ABS) to be installed.
Should You Get A Direct Or Indirect Tire Sensor?
Since indirect sensors do not require any specialized components or maintenance, they tend to be more budget-friendly as compared to direct sensors.
However, direct tire sensors are more reliable and accurate when it comes to identifying improper inflation pressure in tires.
Unlike indirect sensors, direct sensors don’t require repeated calibration whenever tires are inflated or changed.
Another major drawback of indirect sensors is that they determine pressure issues by measuring the imbalance in tire rotation speeds.
Additionally, in case all four tires are underinflated, the indirect sensor will not be able to identify and indicate the issue because the tires will be rotating at similar speeds.
Therefore, if you’re looking for significant cost savings and greater control in calibrating your tire sensors, you should choose indirect tire sensors.
However, if vehicle safety is your priority and you are not constrained by a tight budget, you should consider installing direct tire sensors in your vehicle.
Can You Drive Without Tire Sensors?
Tire sensors have been required by law in the United States since 2007, and due to this, all vehicles manufactured after 2007 are already equipped with a tire pressure monitoring system before they’re sold.
Other than that, the European Union also mandated the use of tire sensors after 2014, meaning that while you can still drive your vehicle without tire sensors, it may be a violation of the laws depending on the country you live in.
What Can Damage A Tire Sensor?
Tire sensors often get damaged during the tire mounting and demounting process since the sidewall ends up trapping the sensor against the rim, which occurs because the tools used to remove and re-install tires are not designed to safely deal with the TPMS (Tire Pressure Monitoring System).
Additionally, corrosion, harsh weather conditions, and exposure to certain materials can also cause damage to tire sensors.
For example, contact with road salt used during winters accelerates corrosion and leads to inaccurate inflation pressure readings.
Are Tire Sealants Safe for Tire Sensors?
Slime-based tire sealants are used as an instant fix for flat tires, added into the tire through the valve stem so that the sealant can block the puncture with its particles.
However, tire sensors are also installed on the valve stem, which means that the sealant can accidentally end up clogging around your sensor and prevent it from taking any measurements.
As well, sealants marked as “tire sensor safe” use fiber seal technology which ensures that the particles are able to pass through the sensor.
Therefore, as long as you’re using a ‘tire sensor safe’ sealant to fix your punctures, you don’t need to worry about damaging your tire sensors.
Can All Four Tire Sensors Go Bad?
Although this happens very rarely, all four tire sensors can indeed stop working and malfunction at the same time.
In case you’re not getting any pressure readings from any of the transmitters, you should first check to see if the problem lies with the display or receiver.
However, if the receiver is working fine, you should seek a professional mechanic to fix (or replace) your tire sensors.
How Can You Tell Which Tire Sensor Is Bad?
There are several signs that can help you identify bad tire sensors, such as not getting any pressure readings from one particular sensor.
Another cue could be that the sensor light stays on even when the tires are fine.
Additionally, if your sensor is not calibrated, you may notice too much variation in its readings as compared to the other sensors.
Overall, in any of these situations, you should check the inflation pressure with an actual pressure gauge and compare the readings with that of the tire sensor.
How Much Does It Cost To Replace A Tire Sensor?
The cost of replacing tire sensors depends heavily on the type and brand of sensors you’re using.
However, the typical range of a sensor service kit is $5 to $10 per wheel while replacing the sensors can cost anywhere between $50 to $250 for each sensor.
Can You Replace A Tire Sensor Yourself?
Although it may seem like a great idea to replace your tire sensors yourself, you should avoid doing so, as you may end up accidentally damaging the sensors or installing them incorrectly.
Therefore, if you need to get a tire sensor replaced, it’s best to seek professional help if you’re not experienced enough to properly work with the tires.
Where Can You Get Tire Sensors Replaced From?
As well, you can check with your local car dealers and mechanics since most of them will be able to replace your tire sensors for you.
Can A Tire Sensor Drain Your Vehicle’s Battery?
Tire sensors do not drain your vehicle’s battery because they use their own lithium-ion batteries for power, which are only switched on when the engine is also running.
Normally, tire sensor batteries can last for as much as 5 to 10 years, however, vehicle owners often have to get the entire sensors replaced when the battery dies because of the difficulty in extracting the batteries from the sensors.
Do You Need To Replace Tire Sensors When Replacing Tires?
You don’t need to replace the tire sensors if you are replacing your vehicle’s tires, because if you’re using direct sensors, they will calibrate automatically once you’ve driven a few miles.
However, for indirect tire sensors, you may have to reset and calibrate them again after you replace the tires.
How Do You Reset A Tire Sensor?
The reset button for direct tire sensors is usually located beneath the steering wheel, which simply requires you to press and hold that button until the light blinks three times.
You should note that it takes about 20 minutes for the tire sensors to actually reset and start taking the right readings after you release the button, so it’s recommended to start the car and drive a few miles after doing so.
Afterward, once you’ve covered several miles, the sensors will adjust to your tires and start monitoring the inflation pressure correctly.
Why Is Your Tire Sensor Light On When The Tires Are Fine?
If your sensor lights are on even though you checked that the tires have adequate inflation pressure, this generally means that your tires are cold.
Low temperature pushes the inflation pressure down about 10-15%, which therefore triggers the tire sensor indicator in your dashboard.
However, once you’ve driven for a few miles and the tires heat up, the inflation pressure will get back to the proper level and the tire sensor light will turn off.
If you are looking to learn more, you can also check our posts on how long do f1 tires last, why is tire pressure light is still on after filling tires, and the tire load range SL.
Tire sensors tell you in real-time whenever the inflation pressure of your tires is out of range. Indirect sensors use the revolution rate while direct sensors monitor the inflation pressure.
All tire sensors come with their own batteries that last for around 5 to 10 years. However, once the battery dies out or the sensors corrode, they must be replaced entirely, and replacing them can cost anywhere between $50 to $250 per transmitter.