The polar plunge that has chilled much of the nation does more than bring out ice scrapers and antifreeze. It can trigger vehicles’ tire pressure monitoring systems overnight, sending nervous drivers to dealers and service centers.
If you live in an area where you encounter snow during the winter months, your TPMS light has probably already signaled a change in tire pressure, but you may not be expecting it if you live in sunnier climates. It could also happen if you drive from a warmer area to spend a vacation day in the snow.
Here’s why a cold snap affects tire pressure and sets off the tire pressure monitoring system (TPMS) warning lamp:
For every 10-degree-Fahrenheit drop in temperature, tire air pressure decreases about 1 pound per square inch (psi), said David Cowger, global sub-system manager for tires in General Motors’ Tire and Wheel Lab. On top of that, tires slowly lose air anyway – the equivalent of between .25 and .5 psi per month – because air passes through rubber.
“So if you last checked your tire pressure a few months ago when it was 70 degrees and now it’s 20, a tire with a recommended psi of 35 could be down to 27 or 28 and set off the TPMS warning,” said Cowger. “It’s very common when the first cold weather arrives.”
Unless there are issues such as punctures or damage, the TPMS light will turn off once the tires are properly inflated.
It’s important to keep tires inflated to their recommended psi (found on a placard on the driver’s side center pillar or door edge), said Cowger. Underinflated tires can wear out prematurely, negatively affect vehicle handling, reduce fuel economy and overheat, leading to blowout.
Tire pressure monitoring systems have been required on new vehicles since 2007. The National Highway Traffic Safety Administration requires the TPMS to display an alert when a tire’s pressure drops 25 percent below its recommended psi.
GM, along with technician training experts from ACDelco, recommend these tips for cold-weather tire care: