A modern car is a complex computer on wheels that constantly monitors the state of dozens of systems. When the driver gets behind the wheel and turns the ignition key, many indicators flash on the dashboard, most of which go out immediately after starting the engine. But if they were caught in flames. horseshoeThis is a signal that cannot be ignored.
This symbol, technically referred to as the indicator of the tyre pressure control system (TPMS), may indicate both a banal puncture of the wheel and more complex problems with electronics or braking system. In some car models, a similar pictogram may signal a low level of brake fluid or malfunction. lock-out. Understanding the context and being able to quickly diagnose the cause of a light bulb can protect you from costly repairs or dangerous traffic situations.
In this article, we will discuss in detail why this indicator lights up, how to react correctly to its appearance and what actions should be taken to eliminate the malfunction. We will look at the differences in the system’s behavior across different types of cars and explain when professional intervention is required and when it is possible to manage on your own.
Basic value of the tyre pressure indicator
The most common interpretation of a horseshoe sign with an exclamation mark is activation of the system. Tire Pressure Monitoring System. Sensors installed inside wheels or analyzing the speed of rotation of wheels through the ABSThe pressure drop is below the critical threshold. This usually occurs if the pressure has dropped by 20-25% of the manufacturer’s recommended value.
Reducing tire pressure is not just a discomfort when driving, but also a direct threat to safety. With insufficient pressure, the contact area of the tire with the road increases unevenly, which leads to overheating of the rubber and a sharp increase in the braking distance. Besides, fuel This can increase by 5-10% as the engine has to put more effort into rolling the flat wheel.
It is important to note that the indicator can burn constantly or flash. If the light bulb is on with even light, it usually indicates a physical decrease in pressure in one or more wheels. If flasher within a minute after the ignition is turned on, and then burns constantly, this indicates a malfunction of the monitoring system itself - for example, the power element sat down in the sensor or the signal receiver failed.
- 🚗 A puncture of a tire or slow air leakage through a nipple or disc.
- 🌡️ A sharp change in air temperature (cooling reduces tire pressure).
- 🔋 Battery discharge of the internal sensor TPMS (relevant for systems with direct monitoring).
- 📡 Failure of the receiving module or electronics of the car.
Sometimes the cause of false alarm is a recent change of wheels or seasonal reshoes, if the master has not performed the procedure. calibration. In such cases, the car’s computer continues to operate with the old parameters and perceives normal pressure as an anomaly.
Brake system and fluid level connection
Although the “horseshoe” is most commonly associated with tires, in a number of cars (especially older models or certain brands), this symbol may duplicate the functions of the brake indicator. This is because the systems TPMS and ABS They're tightly integrated. If ABS sensors detect anomalies in the rotation of the wheels, they can transmit erroneous data to the TPMS control unit.
However, there is a more critical reason for a similar symbol to light up or to light up with it – low levels of light. brake fluid in the expansion tank. When the liquid level falls below the MIN mark, the sensor closes the circuit, and the warning lights up on the instrument panel. Ignoring this signal can cause the brakes to fail.
⚠️ Attention: If the indicator caught fire during movement and is accompanied by a change in the brake pedal (it has become softer or fails), you must immediately stop in a safe place and check the level of brake fluid. Operation of a car with a faulty braking system is strictly prohibited.
It is also worth checking the condition. brake-pad. On some cars, worn pads with abrasion sensors can cause various warning lamps to light up, although more often a separate symbol is used for this. However, a comprehensive diagnosis of the chassis when any alarms appear will not be superfluous.
Direct and Indirect Monitoring: What’s the Difference
To respond properly to the horseshoe signal, you need to understand what type of pressure control system is installed on your car. There are two main types of systems, and the way they work is radically different, which affects the methods of diagnosis and error reset.
Direct System (Direct TPMS) It uses physical pressure sensors installed inside each wheel on the valve. They transmit accurate numerical data about pressure and temperature in real time. The advantage of such a system is high accuracy and the ability to see the pressure in each wheel separately on the screen of the onboard computer.
Indirect System (Indirect TPMS) It does not have separate pressure sensors. It uses the system's wheel speed sensors. ABS/ESP. The computer analyzes the speed of rotation: the deflated wheel has a smaller diameter and rotates faster than the pumped. If the difference in rotation speed exceeds a predetermined threshold, the indicator lights up.
How to determine the type of system on your car?
If you have the option to display the exact bar pressure or PSI for each wheel on the menu screen, you have a direct system. If the menu only shows a check Tire Pressure warning without numbers, it is likely an indirect system based on the analysis of wheel rotation.
The difference in service is significant. For a direct system, replacing the sensor requires disassembling the wheel and often replacing the sensor itself (the battery life is 5-10 years). For an indirect system after tyres are pumped or replaced, a procedure is required. calibration (reset)Otherwise, the system will not work properly.
Algorithm of actions when the indicator is lit
If the dashboard caught fire "horseshoe with an exclamation mark", do not panic, but also postpone the check for later can not. There is a clear algorithm of actions that will help to quickly identify the cause and eliminate it.
The first thing you need to do is visually inspect all four wheels. Often a serious puncture is visible to the naked eye. If the tires look normal visually, find the nearest gas station or tire fitting where there is a pressure gauge. Check the pressure in all wheels, including spareIf it's full-size.
Compare the values obtained with the recommended ones. The pressure plate is usually located on the driver's door counter from the lock side or on the inside of the gas tank hatch. Don’t focus on the numbers knocked out on the sidewall of the tire – this is maximum-pressureNot recommended for comfortable driving.
☑️ Procedure for the TPMS signal
After bringing the pressure to normal, the indicator can go out after a few kilometers of the way (automatic calibration). If this does not happen, you will need to manually reset the error through the menu of the onboard computer or a special button.
Effects of seasonal factors and temperature
One of the most common reasons for the TPMS indicator to burn is the change of season. The physics of the processes is simple: when the ambient temperature decreases, the pressure in the tires drops. For every 10 degrees Celsius decrease in temperature, the pressure drops by about 0.1 bar (1.4 PSI).
Imagine a situation: you pumped the wheels in the summer at +30°C to a normal of 2.2 bar. Autumn came and the temperature dropped to 0°C. Tire pressure will drop by about 0.3 bar to 1.9 bar. If the alarm threshold is set to 2.0 bar, the indicator will light up, although puncture Maybe it's not.
However, relying on the weather effect is dangerous. Often, the temperature drop simply "makes" the wheel, which already had a microleak or an old nipple poisoned the air. Therefore, even in winter, seeing the signal, it is necessary to check the tightness of the tires.
When changing tires seasonally, always request the installation of new brass or nickel-plated nipples in the tire fitting. Old rubber caps and nipelas often cause a slow air leakage that is difficult to notice visually.
It is also worth considering the heating of the tires during the movement. The pressure in hot tires is always higher than in cold tires. Manufacturers specify the standards for cold-tyre (The car stood for at least 3 hours or traveled less than 2 km). If you pumped the hot wheels to normal, then when cooling down, the pressure will fall below the permissible, and the indicator will light up again.
Table: Comparison of symptoms and causes
For ease of diagnosis, we will give a comparative table that will help to quickly determine the source of the problem, analyzing the behavior of the indicator and the car.
| Symptoms. | Probable cause | Action |
|---|---|---|
| The indicator is always on. | Low pressure in one or more wheels | Check the pressure, pump or replace the wheel |
| The indicator flashes 60-90 seconds, then burns | TPMS system malfunction (sensor, receiver) | Scanner diagnostics, sensor replacement |
| It only lights up in the cold. | Temperature pressure drop | Reduce tires to normal, taking into account the temperature |
| Burning along with ABS/ESP | Problem with ABS sensors or wiring | Urgent diagnostics of the chassis and electronics |
As you can see from the table, the behavior of the indicator gives an important clue. If blinking is accompanied by loss of control or knocking, it can be a serious malfunction of the suspension or steering, which requires immediate access to the service.
Resetting and calibration procedure
Once you have fixed the cause (plain your tires, paste a puncture, or replace the sensor), the system often needs to be “teached” to work with new parameters. The procedure for resetting depends on the make and model of the car, but the general principle is the same.
On most modern cars, the reset is done through the dashboard menu or multimedia system. You'll need to find a section. Car settings → Tires. or TPMS. There's a button. Set or Calibrate. By pressing it, you confirm that the current pressure is the norm.
Typical path on the menu:Vehicle → Settings → Tire Pressure Monitoring → Set Pressure
or
Car → Status → TPMS → Reset
Some models (e.g. Toyota, Lexus, Honda) may require a sequence of actions with buttons on the steering wheel or torpedo. For example, hold the setting button until the indicator blinks three times. After that, you need to travel several kilometers at speeds above 40 km / h, so that the system records new data.
⚠️ Attention: Never perform a system reset (calibration) without checking the physical pressure in the tires with a pressure gauge! If you drop an error on a flat tire, the system will consider emergency pressure as normal and will not warn you of a real puncture in the future.
Resetting the TPMS error is possible only after the pressure in the tires is physically brought to normal. Calibration on flat wheels makes the safety system useless.
If the indicator continues to burn after all the procedures, it is possible that one of the sensors has failed or an error has occurred in the system, which can only be considered by a professional diagnostic scanner.
Frequently Asked Questions (FAQ)
Can I drive if the horseshoe indicator with an exclamation mark is on?
A short trip to the nearest place to check the pressure is acceptable if you are sure that the tire is not fully flat. However, long-term operation with a burning indicator is dangerous: you do not know the real condition of the wheels, which increases the risk of aquaplaning, tire rupture and accidents.
How much does it cost to replace the tire pressure sensor?
The cost consists of the price of the sensor itself (from 2000 to 6000 rubles per unit depending on the brand and type) and works on disassembly / assembly and programming. Original sensors OEM It is always more expensive than universal analogues.
Why did the lights start to burn immediately after the tyre?
Most likely, the wizard did not conduct the procedure of binding sensors or resetting the system. It is also possible to damage the sensor during installation or use metal caps instead of plastic (the metal can "stick" and damage the nipple, causing leakage).
Does the type of rubber (spikes/Velcro) affect the sensor readings?
The type of tread itself does not affect the operation of electronics. However, winter tires are more sensitive to temperature changes, so in winter signals of pressure drop are more frequent. It is important to pump winter tires according to the recommendations of the car manufacturer, and not "by eye".