Does TPMS 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 supplied into Europe, 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.

The process when changing the tyre for a vehicle with TPMS 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.

Vehicles older than this are typically fitted with standard rubber valves, when we do a tyre replacement for these vehicles the new valve is included in the price. However, with TPMS systems on newer vehicles, it is a little different.

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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 any issue, 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 such as 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 the ABS (Anti-Lock Braking) ring, resulting in the reading being less accurate in comparison to the direct TPMS. This is triggered by a significant drop in the rolling circumference of the tyre, meaning it must have drop a considerable amount of pressure for it to activate the light on your dash.

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 on these vehicles you must manually reset the TPMS light or it will display a low-pressure warning.

When do I need to replace my TPMS system?

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.

They may also need to replaced due to damage, this could happen from colliding with a kerb at the wrong angle or by putting air into your tyres a little too aggressively!