Tyre Pressure Sensors: How They Work & How to Reset Them
FixMyCar explains how tyre pressure sensors work.
Book a car repair nowCharlotte Phillips
Tuesday January 16 2024
6 min read
Your tyres are a fundamental part of the safety and functioning of your car. While it’s important to keep an eye on the overall condition of your tyres, you should also ensure that they 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 work, keep reading.
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 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 the tyres are properly inflated, which is crucial for vehicle safety, performance, and fuel efficiency.
When the sensors detect low pressure compared to the recommended tyre pressure, they trigger a warning light on the vehicle's dashboard, alerting the driver to top up the 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 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 like 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 than 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 vehicles, and today, you will find that most 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 do you 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.
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, 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 indicate 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's make and model. You can often find instructions in the vehicle's owner manual or consult a mechanic or dealership for guidance.
Note: TPMS resets must only be 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 your vehicle's tyres 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). The TPMS reset button may sometimes be 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
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 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 to reset all the sensors. Some cars 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 need help 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
The TPMS sensors may sometimes 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 a 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 re-establish communication and functionality.
Looking for a qualified mechanic to inspect your tyres? At FixMyCar, our network of garages and mechanics are here to help.
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