What Does TPMS Stand For?
TPMS stands for Tyre Pressure Monitoring System. It is a mandatory safety system on all new cars sold in the UK since November 2014, designed to alert drivers when tyre pressure drops to a level that could compromise safety or fuel efficiency. The system uses small sensors mounted inside each wheel to monitor pressure in real time.
Direct vs Indirect TPMS
Direct TPMS uses individual pressure sensors inside the tyre that transmit live readings to the car's computer. Indirect TPMS uses the ABS wheel speed sensors to detect when one wheel is rotating faster than the others — which happens when a tyre loses pressure and its diameter shrinks. Direct systems are more accurate; indirect systems are simpler and require no sensors to replace.
When the Warning Light Comes On
The TPMS light typically triggers when pressure in one or more tyres falls to 25% below the recommended level. At that point the tyre is already significantly under-inflated and your grip and fuel economy will be affected. Check pressures immediately at a garage or petrol station, and investigate whether a slow puncture is to blame.
TPMS and Tyre Changes
When fitting new tyres, TPMS sensors must be either reused from the old tyre or replaced. The sensor valve stems can corrode over time, particularly on vehicles in coastal areas near Newport. Newport Mobile Tyres checks and tests TPMS sensors as part of every tyre fitting, and can source replacement sensors for all vehicle makes and models.
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