Do TPMS Sensors need to be replaced when I replace my tyres?
TPMS systems remain a bit of a mystery to many of our customers, so we thought we would try and explain it a little better for you! In short, any vehicle from 2014 onwards, by law, must be fitted with some sort of TPMS system, there are two ways that this can be done - indirect TPMS and direct TPMS.
Older vehicles are typically fitted with standard valves, this is simply a small rubber valve, when we do a tyre replacement the new valve is included in the price. However, with TPMS on newer vehicles it is a little different.
What are the two different types of TPMS?
Direct TPMS - this is operated by a sensor, 90% of the time it will display the actual tyre pressures for each individual tyre without problem, in the event of any abnormal change on pressure the sensors will send more frequent signals to the dashboard in order to worn the driver. It is effectively a radio transmission signal to the cars ECU (Electronic Control Unit), this allows a 'real time' reading to be displayed to the driver.
Newer model Mercedes-Benz vehicles operate with direct TPMS, they also use an automatic re-learning system, meaning once you drive the vehicle after a tyre change the sensor will work itself out and adjust to the new pressures.
Indirect TPMS - these don't have sensors, instead they use an ABS ring, resulting in the reading being nowhere near as accurate as the direct TPMS because the sensor is triggered by a significant drop in the rolling circumference of the tyre, meaning it must drop a significant amount of pressure for it to trigger the light.
VW, Audi, Seat and Skoda (otherwise known as the 'VAG' group) generally operate on indirect TPMS with very few exceptions. When a tyre is changed or air pressures adjusted on these vehicles you have to manually reset the TPMS light.
The process when changing the tyre is the same principle whether it is direct or indirect, a system check is always included, however it is recommended that a direct TPMS valve has the seal kit replaced on the sensor valve stem. We also do a diagnostic check on the sensors, this checks the sensor's battery condition and ensures it is transmitting correctly.
When do I need to replace my TPMS Sensor or its Valve?
Normally a TPMS Sensor has a battery life of 6-10 years, if there is a low battery issue we can diagnose this with specific tools and replace them. Sometimes the sensors can be corroded causing its electronic components to fail, in this instance we can replace them with new ones.
If the valves are a certain age they can become prone to corrosion and leaking, if we think they need to be changed we will recommend this to the customer and let them know which part of the sensor is failing and the differing costs on fixing these, the components can range from a matter of pence up to £100, so it is impossible to foresee this cost!
If you're still unsure about your TPMS system or whether you even have TPMS, give us a call today on 0333 444 5454 or email firstname.lastname@example.org
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