[Philip Fisher]

Mine has a direct system with the actual pressure of each tyre displayed in the centre screen. I bought a set of sensors for my winter wheels for 176 quid from Volvo. Surprisingly they worked out the box and did not require coding to the car.

That said I never look at the pressure display from one week to another. I rely on an alert from the system. That and of course being sensible about where I drive, looking at my tyres periodically for any signs of damage, uneven wear or bulging etc..

As for aftermarket tpms i have a tyrepal system in the motorhome. It was 100 quid about 5 years ago. It is a reliable bit of kit and causes me no trouble. Sensors are not self charging....