Tyre pressure sensors - How they work & how to reset them
Charlotte Phillips, 5 months ago
5 min read
- Advice
- howto
WhoCanFixMyCar discusses everything you need to know about how your tyre pressure sensors work
Your tyres are a fundamental part of the safety and functioning of your car. While it’s not only important to keep an eye on the overall condition of your tyres regularly, you should also make sure that your tyres are inflated to the correct pressure at all times.
This is where your tyre pressure sensors come in handy. If you’re wondering what these sensors are and how they function in your car, continue reading on to find out more.
How do tyre pressure sensors work?
Tyre pressure sensors, also known as TPMS (Tyre Pressure Monitoring Systems), are electronic devices designed to monitor the air pressure inside vehicle tyres. They are typically installed on each tyre, either on the valve stem or as part of the tyre's inner lining.
The primary function of tyre pressure sensors is to provide real-time information about the tyre pressure to the driver or the vehicle's onboard computer system. This information helps ensure that the tyres are properly inflated, which is crucial for vehicle safety, performance, and fuel efficiency.
When the tyre pressure sensors detect low pressure in comparison to the recommended tyre pressure, they trigger a warning light on the vehicle's dashboard alerting the driver to top up their tyres.
There are two main types of TPMS:
Direct TPMS
This type of system uses individual sensors attached to each tyre's valve stem or integrated with the tyre itself. These sensors measure the actual tyre pressure and transmit the data wirelessly to a receiver in the vehicle. Direct TPMS provides accurate and precise tyre pressure readings.
Indirect TPMS
This system indirectly estimates tyre pressure by monitoring other vehicle components, such as wheel speed or ABS (Anti-lock Braking System) sensors. It relies on the principle that underinflated tyres have a smaller diameter and rotate at a different speed compared to properly inflated tyres. However, Indirect TPMS is less precise than direct TPMS and may require calibration.
Do all cars have tyre pressure sensors?
Tyre pressure sensors are standard for all new cars and today you will find that the majority of cars on the road have TPMS sensors fitted in some way.
In Europe, as of 1st November 2014 all new passenger car models released must be fitted with a TPMS so if your car was manufactured from 2014 onwards, you can be assured that yours is equipped with a tyre pressure monitoring system.
How to know your tyres are flat without tyre pressure sensors
For vehicles that don’t come equipped with a TPMS, there are several things you can look out for to determine if your tyres are running low on air.
Visually inspect your tyres to check if any of them appear visibly deflated, looking out for any signs of sagging or bulging.
Use your hand to feel the tyres. If one tyre feels significantly softer than the others, it may indicate a flat or underinflated tyre.
If you notice any pulling to one side, vibrations, or a sudden change in steering response, it could be an indication of a flat tyre.
Check for any damage or objects embedded in the tyre, such as nails, screws, or other sharp objects that could cause a leak.
How to reset tyre pressure sensors
While the procedure for resetting TPMS sensors is similar across most manufacturers, the exact steps depend on the vehicle make and model. In many cases, you can find instructions in the vehicle's owner manual or consult a mechanic or dealership for guidance.
Note: It's important that TPMS resets are typically done after addressing any underlying issues, such as inflating the tyres to the correct pressure or replacing faulty sensors.
To reset the tyre pressure sensors, you can follow these general steps:
Step 1
Ensure that all the tyres on your vehicle are inflated to the recommended pressure specified by the manufacturer.
Step 2
Locate the TPMS reset button. Some vehicles have a specific button for resetting the tyre pressure monitoring system (TPMS). In some cases, the TPMS reset button may be located under the steering wheel or on the centre console, however you can consult your owner's manual to find the location of this button.
Step 3
Turn on the ignition. Insert the key into the ignition and turn it to the "on" position without starting the engine.
Step 4
Press and hold the TPMS reset button for a few seconds until you see the TPMS warning light on the instrument panel flash or illuminate
Step 5
Release the TPMS reset button after holding the button for the specified time in your owner’s manual.
Step 6
Wait for the TPMS to reset: The TPMS warning light may continue flashing for a short period, and then it should turn off. This indicates that the system has been reset successfully. The time it takes for the TPMS to reset can vary, so it's important to be patient and allow it enough time.
Step 7
Repeat the process for each tyre: If your vehicle has individual tyre pressure sensors, you may need to repeat the process for each tyre in order to reset all the sensors. Some vehicles have a single reset button that resets all the sensors simultaneously.
It's important to note that the exact steps and process may vary depending on the make and model of your vehicle. If you're unsure or having difficulty resetting the tyre pressure sensors, it's recommended to consult your vehicle's owner's manual or contact a professional mechanic for assistance.
Why do you need to reset tyre pressure sensors?
There are a few different reasons why you might need to reset tyre pressure sensors:
Correcting inaccurate readings
Sometimes, the TPMS sensors may provide incorrect readings due to various factors such as temperature changes, sensor malfunctions, or low battery power. Resetting the sensors can help recalibrate them and ensure accurate pressure readings.
Replacing tyres
When you replace or rotate your vehicle's tyres, the TPMS sensors may need to be reset to recognize the new tyre positions. This is necessary so that the system can continue monitoring the correct tyre pressures after the tyre change.
Low battery or sensor malfunction
If the TPMS sensor batteries run low or if there's a malfunction in one of the sensors, resetting the system can help reestablish communication and functionality.
Looking for a qualified mechanic to inspect your tyres? At WhoCanFixMyCar, our network of over 15,000 garages and mechanics are here to help.
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