Troubleshooter: Why does my tire light come on in the cold?

It’s predictable as death and taxes. The first frost hits the country, and service shop phones light up like Christmas trees with the same question: “why is my tire light on?”

Tire pressure monitoring systems have been mandatory for new vehicles since 2007. Since then, they’ve evolved to be easier to use and to provide pressure readings for individual tires on the instrument panel. A few kind automakers like Nissan and Infiniti have incorporated an indicator to alert you when the tire has reached the correct top-up pressure.

So why do sudden ambient temperature drops set them off?

This is a key reason why some choose to fill performance tires with nitrogen. This pressurized gas contains almost no moisture, resulting in lower pressure variances.

So why not just drive to the dealership and have their staff top up the tires? First, the distance you may have to travel (compared to a neighbourhood gas station or a home compressor), may not be good for a tire that’s even slightly off its pressure and, you risk damaging it. Second, it will take a whole lot of time to drive there, park, find someone to ask, get an employee to bring the vehicle in, and top up your tires. It’s akin to asking someone to show you how to put fuel in the tank.