Why TPMS Lights Are Such a Pain in the You-Know-What

TPMS light

Here we are, November again, and it’s already getting below freezing here overnight in Boston. You know what that means don’t you? It’s the time of year that my wife starts hassling me about how her low tire-warning light, or tire-pressure monitoring/TPMS light is coming on every morning.

I have a couple of tricks up my sleeve, but before I divulge such pertinent information, let me tell you all why it’s happening.

It’s all because of thermodynamics, or, ambient temperature vs. standard pressure.

Remember in science class, when you studied Galileo, thermal expansion and how heated gasses, like air or oxygen, expanded? No? Me neither…

But, what this means is that the air trapped in your tires expands when it’s hot, and shrinks when it’s cold. So your car thinks that it has less pressure in the tires during cold months, and thinks it has more air during the hot ones. It not only “thinks” that it has more or less air, it actually DOES!!

So, you might ask, how do we fix it?

1. Nitrogen

Nitrogen is a less volatile gas when it comes to ambient temperature fluctuations. Once filled with pure nitrogen, tires are far less likely to go up or down much in pressure therefore keeping that pesky TPMS (tire-pressure monitoring system) light off. Keep in mind though, that most shops or service stations DO NOT sell nitrogen. SO, it is a little tricky to find, and a little more expensive than the air you breathe.

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2. Fill your tires on a cold morning

I know, it is a pain to fill your tires on the warmest of days, never mind the frigid ones, but this tip works. Find the coldest day in the next week or so, and fill your tires as early in the morning as possible. When you do this, at the lowest temp during the day, your tire pressure will only go up – keeping that pesky light off. Just keep in mind that you should recheck tire pressure before the summer months, as the pressure might get too high in 80-degree plus days.

So, that’s it! Fill the tires when it’s as cold as possible and keep that tire light off (and your wife off your back).

Written by Rob Grant, Lead Service Advisor, Openbay 

Whether you need a hand with your tires, or any other maintenance or repair, check out Openbay to compare, book and pay for local auto repair service.