How TPMS Works
Tyre Pressure Monitoring Systems (TPMS) use sensors inside each wheel to measure tyre pressure and temperature. If pressure drops significantly below the recommended level, the system alerts you via a dashboard warning light.
There are two types: direct TPMS, which uses physical pressure sensors inside the tyres, and indirect TPMS, which estimates pressure based on wheel speed data from the ABS system. Direct systems are more accurate and now standard on new vehicles.
What the Warning Light Means
A steady TPMS warning light usually indicates one or more tyres are underinflated. Check pressures immediately and inflate to the correct levels. A flashing TPMS light often indicates a sensor fault or communication error, requiring professional diagnosis.
If the light remains on after correcting pressures, a sensor may be damaged, have a depleted battery, or need recalibration after tyre fitting.
TPMS Sensor Replacement
TPMS sensors have internal batteries that typically last 5 to 10 years. When a battery fails, the entire sensor unit is usually replaced. Mobile tyre fitting technicians carry replacement sensors for common vehicles and can programme them to communicate with your car's computer system.
Always inform your mobile fitter if your vehicle has TPMS, as this affects how they remove and refit wheels and whether sensor replacement or recalibration is needed.
