A vehicle is a possession that many take pride in, but it comes with its fair share of demands. One of the most crucial requirement is knowing at least the primary elements of the vehicle, their functionality, and how to take care and maintain them. Tyre pressure is a critical issue that will affect drivers safety if not addressed and can be easily overlooked; car manufacturers have developed a device that detects low or high tyre pressure and warns the driver with a flashing light on the instrument cluster.

So, what is a car tyre pressure sensor,  how does it work, and where is it located?

A tyre pressure sensor is a gadget that monitors the air pressure in a tyre. It is part of the Tyre Pressure Monitoring System (TPMS) that reports to the driver when tyre pressure is low. When the pressure drops to a pre-set level, for example, 25% less than the minimum required tyre pressure, the sensor sends signals to alert the driver. The driver receives the message on the dashboard as a low-pressure warning light, a pictogram display, gauge reading or a warning beeping sound.  

Where is the tyre sensor located? 

The sensor is fitted inside the pneumatic tyres for the direct Tyre-Pressure Monitoring System (dTPMS) or outside for the indirect Tyre-Pressure Monitoring Systems (iTPMS). 

For dTPMS, the sensor is mounted inside the tyre in the inner part of the rim, which is an advancement of the earlier technology, and it gives an accurate reading at a given time. The sensor appears as a small cylinder and is easily visible when a tyre is detached from the rim. On the other hand, an indirect TPMS (iTPMS) uses a sensor mounted outside the tyre.

In iTPMS, the ABS wheel speed sensor is used, which is an older tech that detects wheels rotating at different speeds. Same size tyres with varying tyre pressures have different radius with the under-inflated tyre having the smaller rolling space and thus turns faster. The sensor detects the tyre with the different rotating speed from the others and sends a signal to the driver. The iTPMS is not very accurate and is more prone to false alarms. It may also not detect when all the tyres deflate at the same rate.

Issues with Car Tyre Pressure Sensor

With age, every electrical gadget deteriorates and worse for the tyre pressure sensors fitted in rough and dusty places. Besides, many factors hinder the proper functioning of the sensor, such as the dirt, debris, heat, and irregular power supply. When the tyre pressure sensor is not functioning correctly, it shows signs such as:

1. Imperfect sensing of the pressure - malfunctioning sensors gives the wrong pressure reading. Such may mislead you into thinking you are low on tyre pressure when it is okay, or indicate the pressure is okay when you are on low pressure. It is safer to not only rely on the pressure sensor but to also regularly use a tyre pressure gauge to check your tyre pressure.
2. Wrong dashboard illumination/warning lights - issues with the sensor sending signals to the PCM or ECU may trigger the false warning to the driver. For example, instead of the warning appearing when a tyre is on low pressure, the opposite may happen. The warning appears when the tyres are okay and disappears when a tyre deflates. The signal may also appear continuously with or without an issue when the sensor malfunctions. 
3. Late warning - the sensor may also send signals too late when it malfunctions. For example, a faulty sensor set to send warning signals when a tyre is 25% deflated may remain dormant without a warning until the tyre loses over 50% of its pressure.

Care and Maintenance of the Tyre Pressure Sensor

Like any other part of a vehicle, the tyre pressure sensor also requires care and maintenance proper functioning. Simple practices can prolong the durability and enhance the performance of the sensors or save your life. Take care of your tyre pressure sensors by:

1. Regularly inspect your car tyre pressure sensor in comparison with the tyre pressure gauge and if you not any difference in reading consult a sensor expert.
2. Pay attention to the dashboard, and if you note any false warning, have your vehicle checked by a technician. Paying attention to the performance of the monitoring system also makes it easy to identify any change in the performance of the sensors, and you can make the necessary arrangements on time. 
3. It is also worth it to have your vehicle thoroughly checked, including the sensors regularly.
4. In case of a malfunctioning sensor, have it repaired or replaced with a new one if it is beyond repair. Make sure to buy from reliable sources. 
5. If possible, upgrade your tyre pressure monitoring system to the modern ones which are more accurate durable and less prone to the false warning.

(Blog from carpart.com.au)