Feature · 3 min read
Tyre Pressure Monitoring System (TPMS) Explained
Warns you when one or more tyres may be underinflated.
What is TPMS?
A Tyre Pressure Monitoring System (TPMS) keeps an eye on your tyre pressures while you drive and warns you when one or more tyres looks underinflated. It's been mandatory on new cars sold in the EU and UK since 2014.
How does it work?
There are two main types. Direct TPMS uses a small battery-powered sensor inside each wheel that measures the actual pressure (and often temperature) and radios it to the car. Indirect TPMS has no sensors in the wheels. It uses the ABS wheel-speed sensors to spot when one wheel is spinning slightly faster than the others — a sign that its tyre has gone soft and is now slightly smaller in diameter.
What does it feel like?
Most of the time you'll see nothing. When pressure drops, a small yellow icon shaped like a horseshoe with an exclamation mark appears on the dashboard. Direct systems often tell you exactly which tyre is low and at what pressure. Indirect systems usually just say 'check tyres'.
Benefits
- ✓Catches slow punctures before they become flats
- ✓Saves fuel — underinflated tyres use more energy
- ✓Reduces uneven tyre wear
- ✓Improves grip and braking by keeping pressures in spec
Limitations
Indirect systems can't detect when all four tyres lose pressure equally — for example, with cold weather. After inflating or swapping tyres, both types usually need to be reset or relearnt via a menu option or button.
Common problems
- ✓TPMS light stays on after inflating tyres — needs a reset
- ✓Direct sensor battery dies after 5–10 years and needs replacing
- ✓Warning triggered by cold weather rather than a real puncture
- ✓Light flashes then stays on — indicates a system fault, not just low pressure