The purpose of the tire pressure monitoring system (TPMS) in your vehicle is to warn you that at least one or more tires are significantly under-inflated, possibly creating unsafe driving conditions. The TPMS low tire pressure indicator is a yellow symbol that illuminates on the dashboard instrument panel in the shape of a tire cross-section (that resembles a horseshoe) with an exclamation point.
That indicator light in your vehicle has a history. It’s a history rooted in years of uncertainty about proper tire pressure and many serious car accidents that might have been avoided had drivers known their air pressure was low. Even now, it’s estimated that a substantial number of vehicles hit the road each day with underinflated tires. However, proper tire maintenance with the aid of a TPMS can and does help prevent many serious accidents.
Before this indicator light became commonplace, knowing whether your air pressure had reached unsafe levels meant getting out, crouching down, and using a tire gauge. With few exceptions, this was the only pressure-checking tool ordinary consumers had at their disposal.
Then, in response to a surge in accidents due to underinflated tires, the US government passed the Transportation Recall Enhancement, Accountability, and Documentation (TREAD) Act. One of the outcomes of this legislation is that most vehicles sold in the United States since 2007 include a tire pressure monitoring system of some kind.
Not every TPMS works the same way. The illumination of the low tire pressure indicator represents the final step in the process of either an indirect TPMS or a direct TPMS.
An indirect TPMS typically relies on wheel speed sensors that the anti-lock brake system uses. These sensors measure the rate of revolution each wheel is making and can be used by on-board computer systems to compare with each other and to other vehicle operation data such as speed.
Based on the rate of revolution of each wheel, the computer can interpret the relative size of the tires on your vehicle.
When a wheel starts spinning faster than expected, the computer calculates that the tire is underinflated and alert the driver accordingly.
So, an indirect tire pressure monitoring system doesn’t actually measure tire pressure. It’s not electronically processing the same kind of measurement you might see with a tire gauge. Instead, an indirect tire pressure monitor simply measures how fast your tires are rotating and sends signals to the computer that will actuate the indicator light when something in the rotation seems amiss.
-- Relatively inexpensive compared to a direct TPMS
-- Requires less programming/maintenance over the years than a direct TPMS
-- Less overall installation maintenance than its direct counterpart
-- May become inaccurate if you purchase a bigger or smaller tire
-- May be unreliable when tires are unevenly worn
-- Must be reset after properly inflating every tire
-- Must be reset after routine tire rotation
Direct TPMS uses pressure monitoring sensors within each tire that monitor specific pressure levels – not just wheel revolution data from the anti-lock brake system.
Sensors in a direct TPMS may even provide tire temperature readings. The direct tire pressure monitoring system sends all of this data to a centralized control module where it’s analyzed, interpreted, and, if tire pressure is lower than it should be, transmitted directly to your dashboard where the indicator light illuminates. A direct tire pressure monitor usually sends all of this data wirelessly. Each sensor has a unique serial number. This is how the system not only distinguishes between itself and systems on other vehicles, but also among pressure readings for each individual tire.
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.
-- Deliver actual tire pressure readings from inside the tire
-- Not prone to inaccuracies because of tire rotations or tire replacements
-- Simple resynchronization after tire rotation or tire replacements
-- Batteries inside the sensors usually last for about a decade.
-- May be included in a vehicle’s spare tire
-- More expensive overall than an indirect TPMS
-- Though simple, resynchronization may require costly tools.
-- Battery rarely serviceable; if the battery is drained, the whole sensor must be changed.
-- Proprietary systems make installation, service, and replacement confusing for consumers and auto shops.
-- Sensors are susceptible to damage during mounting/demounting
Although the methods may be different, both systems serve the same purpose and activate the same indicator light. Even though a TPMS can deliver accurate alerts when properly maintained, it’s not a replacement for manual air pressure checks, consider it just another item in your car maintenance toolbox.
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There’s never a good time for a flat. That’s why Bridgestone DriveGuard tires are masterfully engineered to keep you moving for up to 50 miles at speeds up to 50 MPH without disruption.
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From punctures to improper wheel alignments, there’s a lot that can affect or damage your tires’ ability to maintain pressure. Luckily many modern cars come with sensors to let you know in real-time if there’s a problem. But these tire pressure monitoring systems aren’t infallible, which is why some OEMs are working on updating them.
How does TPMS work?Your car’s TPMS, as with many of its other safety and driver-assistance features, relies on specialized sensors, Car and Driver reports.
Many are mounted in the wheel, TirePlus reports or built into the tire’s valve stem. Most aftermarket systems, The Drive reports, are of one of these so-called ‘direct’ monitoring designs.
As the name implies, direct tire pressure sensors explicitly measure air pressure. These battery-powered sensors send radio signals to a receiver within the car. When the pressure gets too high or low, the TPMS warning light comes on.
Some cars, though, have tire pressure sensors linked into the ABS system. These ‘indirect’ sensors, Bridgestone explains, don’t actually measure pressure, though. Instead, they measure tire rotation. An improperly-inflated tire doesn’t roll at the same speed as a properly-inflated one. So, if the TPMS notices a speed imbalance, it triggers a warning light.
Recently, though, some suppliers have been trying to improve upon TPMS design. BMW and Michelin, for example, have collaborated on a ‘connected tire’ which uses sensors to measure not just pressure, but tire temperature, too. The goal is to use this data to provide the driver with valuable training feedback.
Microsoft and Bridgestone’s new tech can alert you of tire damage in real-time. https://t.co/WTHwWMMV0L
— The Drive (@thedrive) July 3, 2020
In addition, The Drive reports Bridgestone and Microsoft are working on a system that can monitor tire damage as well as pressure. This new system would also detect if the tire hits a pothole or other irregularity, and tag it via GPS. Then, using vehicle-to-vehicle communication, it would let other cars know to avoid that spot.
As of this writing, Microsoft’s ‘TDMS’ is available in new VW, Nissan, Mitsubishi, and Renault vehicles.
It’s unknown when, or if, the technology will spread to other brands. However, it could help prevent some of the problems which can plague conventional tire pressure sensors.
While TPMS is a helpful tool, it’s not infallible. Firstly, the warning light typically only illuminates when the tire pressure is at least 25% too low, Edmunds reports. Secondly, as with engine mounts, catalytic converters, or any other sensor, the ones in your tires can and do break.
Because direct sensors are part of your wheel or tire, they’re subject to road imperfections.
This means a severe-enough impact, such as with a deep pothole, can damage them. As can road debris or severe weather, Cars.com reports. Usually, that’s signaled by the TPMS light flashing, rather than staying lit.
In addition, tire pressure sensors operate using radio frequencies. If the signal gets blocked or encounters interference, you can experience a false malfunction light. This can happen, for instance, if you fit a snow tire that isn’t compatible with your TPMS.
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Tires: they’re your only points of contact with the ground when in a car. Do the smart thing and take care of them! . . Do your P.A.R.T. this National Tire Safety Week! . . P = Pressure | An underinflated tire can result in excessive wear and/or even a blowout. Every month take 5 minutes to check your tire’s air pressure.
It’s safe, saves money, and more fuel efficient. . A = Alignment | Tires are out of alignment? They wear significantly faster and their performance is reduced. No need for a headache, just get your tires aligned! . R = Rotation | Not rotating your tires means uneven handling, traction, and wear. Save yourself money and be safer. Get your tires rotated! . T = Tread depth | Grab some spare change and get a hand from honest Abe himself. If you can see his head when you put the penny against your tire, it’s time for a new set!
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Direct sensors, though, have one more potential failure point. Unlike indirect ones, which are wired into the car’s electronics, direct tire pressure sensors have their own batteries. Over time, these go flat, and the whole sensor needs to be replaced. And, as with replacing sensors for adaptive cruise control or automatic emergency braking, this requires a system recalibration.
For all these reasons, while TPMS is a helpful tool, it shouldn’t replace a regular tire inspection.
Why is proper tire pressure important?OMSK, RUSSIA – OCTOBER 27, 2018: Checking tire pressure on a car fitted with winter tires | Dmitry Feoktistov/TASS via Getty ImagesMaintaining proper tire pressure may not seem as vital as, say, making sure your engine has enough oil. However, it is still an important maintenance task. That’s why OEMs put the recommended tire pressure on a sticker in the door jamb.
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If a tire is under- or over-inflated, Car and Driver explains, it messes with the contact patch. This means your car doesn’t handle as well or as safely. That’s why Chevrolet attempted to use tire pressure to correct the rear-engine Corvair’s flaws.
An incorrectly-inflated tire also doesn’t absorb shock as well, which could result in further suspension or TPMS damage.
Plus, a tire without enough pressure flexes more, AAA explains, which causes excessive heat and accelerated wear. Under-inflation also increases rolling resistance, which makes you burn more fuel.
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In America and Europe, a tire pressure monitoring system is an indispensable element of a car. Most likely, in the near future the same rules will be adopted in Russia.
But even if this system does not become mandatory, nothing prevents it from being installed in a car if the standard TPMS is not provided by the manufacturer: it is much better to find out in time that the wheel is flat than to wait for sad consequences. nine0003
TPMS (tire pressure monitoring system) monitors changes in tire pressure: even a small decrease in pressure in one wheel increases fuel consumption, worsens car handling and increases tread wear.
Now the pressure control system is divided into systems of direct (direct) and indirect (indirect) directions - we will tell you in more detail what it is.
In direct measurement systems, sensors are placed on the valves of all wheels. They can be installed inside or outside. The sensor detects the level of pressure in the wheel and transmits information via radio to the control unit. Here, the accuracy of the readings plays a big role - you can even track a decrease in pressure by only 0.1 bar.
The "direct" system is more expensive than the "indirect" one, but it transmits information more accurately and faster. She, of course, has her own nuances: if you have to swap tires for even wear, then information about this will need to be entered into the control unit. nine0003
The so-called "indirect" TPMS is essentially a software extension for ABS: in its work it uses standard wheel rotation sensors.
The system monitors changes in wheel speed and can diagnose tire pressure loss based on this information.
In this case, we are not talking about exact values, but only signals a significant deviation from the usual pressure - a significant deviation in this case is 0.3 bar, and a dangerous one - 0.5 bar. nine0003
"Indirect" systems may erroneously transmit a signal for a decrease in tire pressure also when:
Uneven load distribution
Frequent change from lane to lane
slippage
Sharp descents and ascents
But this can be adjusted, for example, by setting an alert delay. You can also reboot the system so that it adjusts to different tire pressures at startup.
The AIRLINE range includes 2 models of the "direct" system.
Tire pressure monitoring system TPMS BLACK ATP-MS-01 includes 4 sensors and a receiving module with a color LCD display.
The sensors are mounted on the nipple of the car wheel, measure the pressure and air temperature in the tire and transmit information about the pressure value via radio to the display. When the tire pressure changes, the system transmits information with sound signals and displays it on the display. The pressure and temperature thresholds are set in the display menu. The system can be installed independently - it does not require special skills. nine0003
The receiving module is powered by the car's cigarette lighter socket, there is also a USB output for convenient parallel charging of the smartphone. The kit includes a receiver with a display, 4 external pressure sensors, 4 locknuts, a kit for mounting sensors, a warranty card and instructions. The operating temperature of the sensors is from -40°С to +125°С.
Tire pressure monitoring system TPMS wireless INSIDER SOLYAR ATP-MS-02 includes 4 sensors and a receiving module with a color LCD display.
When the tire pressure changes, the system transmits information with sound signals and displays it on the display. The sensors are marked position, but the wheels can be swapped, everything is reconfigured. The operating temperature of the sensors is from -40°С to +125°С. nine0003
The kit includes a double-sided adhesive tape for fixing the receiving module on the dashboard of the car, it can also be mounted on a Velcro mat.
The receiver module is powered by a built-in lithium-polymer battery, which is charged by a built-in solar panel or a microUSB socket. The kit includes a receiver with a display, internal sensors, a USB-microUSB cable, double-sided tape, a warranty card and instructions. Tire fitting is required for installation, so we recommend contacting a service center for proper installation. nine0003
Pressure control in car tires is implemented using several options for systems with different operating principles.
Manufacturers install standard equipment with direct or indirect control. Freelance versions with different sensors and degree of information content are also known. We will understand the main ways to control pressure and consider the principles of operation of systems.
Tire pressure measurement nine0003
The equipment for monitoring tire pressure, which is provided in the basic configuration, is standard. It can also be released as a paid option. But in any case, such systems are divided into 2 types.
Standard equipment is abbreviated as TPMS, which stands for Tires Pressure Monitoring System. Literally translated, this is “Tire Pressure Monitoring System”. nine0003
The peculiarity of the model with indirect control is that it does not measure pressure. Its work is based on the ABS system, which reads the wheel speed while driving.
Data from the ABS is transmitted to the control unit, which compares the performance with the actual distance traveled for certain periods of time.
If the pressure in the tire has dropped, its actual size also decreases. As a result, such a wheel has to make more revolutions to cover the same distance. The TPMS system captures this difference and gives a signal to the driver. nine0003
Such equipment is inexpensive and, from a mechanical point of view, reliable, because there are no extra sensors that could fail or fail. But the information content and accuracy are not up to par: the system does not display the tire pressure and gives a signal when it drops by at least 30 - 40%.
This option is more informative and consists of:
A piezo or strain gauge reader changes electrical resistance depending on tire pressure. As a result, the control unit processes and transmits to the driver a signal about the changed pressure.
Tire pressure monitoring system
The system is reliable, but sometimes there are problems with the receiving devices. They are placed as close as possible to the sensors - in the wheel arches, here the electronics are at risk of failing due to moisture or dirt. nine0003
These devices are sold separately and adapt to any vehicle. They are divided into 3 categories.
nine0040 Freelance tire pressure monitoring system
These are the main tire pressure monitoring systems that are installed on most modern cars. The choice of devices depends on the expectations for accuracy and reliability, as well as on your financial capabilities. nine0003 Content
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