Why is My Tire Pressure Light on When My Tires are Fine?

Created: May 18, 2021


In this article, we talk about the tire pressure system, reasons why pressure light can be on and lots of other questions. This information will give answers and explain the reasons for the alarm on the tidy.


Popularity and obligation of the tire pressure and monitoring system

The popularity and even the obligation of the tire pressure and temperature monitoring system is easy to explain – it not only helps motorists to keep tires in case of punctures, as well as save money on fuel (flat tires have increased rolling resistance), but literally saves lives. However, much more often this useful feature performs a completely different function – it makes drivers frantically measure the pressure in the wheels or look for services and tire shops that can fix the “glitch”.

Wheel pressure system

A modern pressure and temperature monitoring system is a complex electronic device that includes wheel sensors, a signal receiver, an antenna and an indicator on the dashboard. This system always shows tire pressure: if it is low tire pressure or high tire pressure. Often, all of the above components are helped by the standard ABS system, which is able to read the revolutions on each individual wheel and detect something amiss (a wheel with less pressure will rotate at lower revolutions than a normally inflated wheel on the same axle). In other words, the functionality is not at all as simple as it seems. It can vary greatly depending on the manufacturer and the specific vehicle model.

Tire pressure alarm

There are many situations in which the low or high tire pressure alarm may not work correctly. As a rule, an alarm light on the tidy comes on when one of the wheel sensors breaks down. Usually, a trick pops up after a seasonal tire change and a visit to a tire service – inept servicemen can accidentally damage the sensor when removing / installing a tire. Proving that this happened through the fault of the tire fitter is sometimes very difficult. Another problem may lie in the wheel sensors themselves – they are equipped with non-replaceable batteries with a service life of no more than 5-10 years. When the battery fails, the signal from the wheel is no longer read by the control unit or is read incorrectly.

For forgetful car enthusiasts, the TPMS system reminds of their presence during seasonal tire changes – often drivers simply forget that their car is equipped with an ingenious system and put the wheels on without any hint of sensors.

ABS system

The advanced ABS system can also make its contribution: when overcoming long bends for a long time, a significant difference in the rotational speeds of the wheels of different sides is recorded. In some cases, this is perceived as an alarming situation – the pressure change lamp can be activated. Exactly the same effect is caused by installing a spare wheel or “stowaway” of a different diameter.

ABS system

TPMS system

Changes in weather conditions are one of the common causes of such a problem with low
tire pressure. Winter tire pressure differs from other seasons. The recommended tire pressure is typically between 30 and 35 PSI. Anything less will affect fuel economy and how the vehicle handles. However, in this situation, the light bulb on the tidy often lights up for good reason. When the wheel heats up while driving or when exposed to sunlight, there is a strong expansion of the gases with which the tires are inflated, and when they cool down, they contract. The pressure inside the tire varies commensurately – depending on the temperature. On average, when the ambient temperature drops by 10 degrees Celsius, the tire loses about 0.07 bar, and vice versa. This could well trigger the TPMS.

General information about tire pressure.

Finally, do not write off the reliability of the TPMS itself – it, like all other electronic components of a car, can malfunction. This happens especially often in places with a strong electromagnetic field that interferes with the normal reception of a signal from wheel sensors by the control unit – under high-voltage power lines or near powerful radio signal transmitters.

Useful information about: ESP, tire pressure, engine management, particulate filter;

You don’t always need to rush when the tire pressure light comes on. Sometimes a car just wants to tell you that problems can be expected at some point in the near future, or that some part of the car is approaching the wear limit. However, the following tire pressure lights should not be ignored.

Tire Pressure Monitoring System (TPMS)

What is the problem?
Warning lights for tire pressure and anti-skid systems (ESP) are mandatory on new vehicles from 2013. There are two different systems that measure tire pressure – directly (using sensors in the tires) or indirectly (using data from ABS / ESP). A warning is issued if there is a loss of pressure.

What can happen?
First of all, don’t panic: if you haven’t noticed that your car is behaving differently than usual, it could just be a false alarm or the system has not been properly calibrated after changing tires.

What should I do?
If the TPMS in your car comes on, you should of course always check the tire pressure and correct it if necessary. The correct pressure can be found on a sticker on the tank lid or door pillar, and in the instruction manual.

How can I avoid the problem?
Check tire pressure regularly, do not use tires to the point of wear. Check tire pressure with tire gauges – to be exactly sure that something is going wrong.

Engine monitoring

What is the problem?
There can be a lot of wrong here: a malfunction of the engine control unit, lambda probe, catalytic converter or injection system. You may also have marten damage, such as a gnawed turbocharger intercooler hose with a corresponding loss of power.

What can happen?
Emissions of pollutants increase, engine power decreases, etc.

What should I do?
Always drive to the nearest workshop or call emergency services.

Particulate filter

What is the problem?
In diesel vehicles, particulate filters collect soot, but this must be burned regularly. This may not always work with frequent short haul flights.

What can happen?
The filter may become clogged. The car can also switch to an emergency program in which only low speeds and revs are possible.

What should I do?
The particulate filter needs to “burn out” over long distances at a certain rate. But it’s not that easy, so the best thing to do is get advice at a workshop.

Brake pads worn

What is the problem?
The brake pads are slowly but surely approaching the wear limit.

What can happen?
The braking distance and braking effect are deteriorated.

What should I do?
You can still drive, but don’t postpone your appointment at the brake shop for too long.

ESP warning lamp

What is the problem?
The Electronic Stability Program (ESP) is active and attempts to stop a skidding vehicle by applying the brakes. This often happens on a wet or icy road. Then the ESP light flashes wildly.

What can happen?
ESP usually works fine, but cannot override the laws of physics.

What can I do?
Drive slower, drive carefully, without emergency braking! If the ESP lamp is on continuously, there may be a technical problem in the system – or the ESP is turned off.

ESP warning lamp

Tire pressure: What should be and how to check it – general information.

All drivers know that modern tires are filled with air inside. Less often, a nitrogen mixture is pumped into the tires. But in any case, the tire in its working condition is under pressure. Thanks to this, we can enjoy a comfortable ride and overcome uneven roads without any problems.

It is worth remembering that not only comfort, but also the safety of the driver and passengers depends on the correct tire pressure. Therefore, the tire pressure indicator should be checked regularly.

Tire pressure problem

What should be the pressure in the tire?

The tire pressure should be the same as recommended by the manufacturer of the particular car brand. The indicators differ:

  • for front and rear axles (not in all car models);
  • for partial and full vehicle load;
  • for tires of various standard sizes (if it is provided for by the design of the car).

To find out the recommended pressure for your wheels, you can flip through your vehicle’s manual. In addition, it can be indicated on the inside of the fuel cover, at the place of connection with the driver’s doors, as well as on the edge of the doors themselves. On the sidewall of any tire there is a Max pressure mark, which will tell you the maximum allowable pressure.

Sometimes car owners are confused by the wide variety of units. Tire pressure can be measured in:

  • Pascals (Pa, Pa)
  • atmospheres (atm., Atm) – sometimes in technical atmospheres;
  • bars (bar, bar)
  • pounds per square inch (PSI) – these units are found mainly in American cars.

The unit converter will help you figure out all the complex numbers. Almost every smartphone has it. Such a useful tool is also not difficult to find on the World Wide Web.

Standard Tire Pressure Gauges

To measure the pressure in the wheels, use pressure gauges. Conventionally, all portable tire pressure gauges can be divided into two groups: electronic and mechanical. Let’s consider them in more detail

  1. Arrow keys. Reliable and inexpensive mechanical devices that operate without a power supply. The indicators can be seen on the dial. Manufacturers usually apply two scales for different units of measurement. Pointer manometers can have different accuracy classes. Their disadvantage is their sensitivity to low temperature, humidity and shock.
  2. Electronic. The most modern type of pressure gauge with many advantages. The measurement results are shown on the display in any unit. The electronic pressure gauge has a very wide range of measurements and gives accurate readings. Additional functions can be a flashlight, thermometer, etc.

Of course, such devices have their drawbacks. First, they are ineffective during the cold season. Electronic pressure gauges operate on a power source and are more expensive than others.

The choice of a pressure measuring device should be made based on personal experience and ease of use. Pressure gauges are available in various price ranges. Therefore, every driver can afford such a tool.

Even the simplest pressure gauges can make your journey significantly safer. Therefore, we recommend that you always have this device close at hand.

Alternative methods for determining tire pressure

A significant part of modern cars can be equipped with a tire pressure monitoring system – TPMS. Thanks to this option, the pressure and temperature in the wheels are constantly monitored. And the driver can see the indicators on the on-board computer.

TPMS today is an obligatory component of the complete set of all new cars produced in the EU and some other countries of the world. For many older models, a tire pressure monitoring system can be installed at a workshop.

Indicator caps are also useful for car owners. They are simply screwed onto the top of the tire valve. The indicators, by changing the color, signal a change in pressure and the need to inflate the tire.

Questions and answers

– Wheel pressure in summer, winter

To answer the question “How is the tire pressure different in winter and summer?” you need to remember something about pressure from school physics lessons. Surely most drivers remember that gases tend to contract or expand depending on the temperature. That is why tires require different pumping in warm and cold seasons.

In winter, tire pressure drops. To correct its value, the tire is additionally pumped up.

The wheel heats up in summer. Accordingly, the pressure increases slightly. However, do not rush to release air from the tire. Reducing pressure is advisable in the hottest period of summer.

Seasonal pressure changes are important information that vehicle manufacturers usually do not indicate in their manuals. Despite the fact that each car has individual requirements for inflation of rubber, seasonal fluctuations in the air in the tire will also be different. Tips on the correct pressure in winter will be given by a qualified tire shop.

– Improperly inflated wheels – what can happen?

Car manufacturers never make recommendations for nothing. Your safety and the service life of your vehicle depend on following these tips. Also, improperly inflated tires can cause premature tread wear and even road accidents.

● If the tires are under-inflated

  • driving becomes more difficult and more unpredictable;
  • uneven rubber wear (the tread edges will quickly wear off);
  • fuel consumption will increase;
  • high risk of damage to the disc when falling into the pit;
  • the temperature inside rises.

The use of under-pumped rubber is justified if the car is constantly driving off-road. In this case, the wheels can be deflated by 5-10% in summer and up to 15% in winter.

● If the tires are pumped

  • the central part of the protector is worn out prematurely;
  • driving becomes less comfortable, the driver and passengers feel the unevenness of the road more strongly;
  • accelerated wear of the suspension and its parts;
  • braking worsens, braking distance increases;
  • a high risk of hernias or even ruptures.

Inflated tires are widely used in motorsport to give the car more control. Keep in mind, however, that such cars do not “live” long, and their tires even less.

● If the tires are not uniformly inflated

  • in case of sharp braking, the car can turn around;
  • fuel consumption increases;
  • on a slippery road, the car skids to the side.

– How to check your wheels?

So, the tire pressure needs to be checked and now we clearly know why. Therefore, let’s talk in more detail about the process itself.

– How is it measured?

Measurement of pressure is carried out only in “cold” tires. That is, after operating the car, a certain time must pass, and this is 5-8 hours. This procedure should be repeated monthly. Do not forget to check the readings before a long trip, as well as when the weather conditions change dramatically.

You can check the tire pressure using a pressure gauge in the following sequence:pressure gauge

  1. Remove the cap from the nipple;
  2. Connect the pressure gauge to the nipple and hold it for 1-2 seconds (a hiss should be heard)
  3. Reset the values and repeat with the remaining wheels. Don’t forget about the spare tire.