What does lf mean on chevy sonic?

When You see If as a message display in Your Chevy Sonic, it means that low tire pressure needs to be addressed. Your tire air pressure should be checked once a month using the same tire gauge. Low tire pressure can be dangerous and could cause a blowout. Low pressure could result from a leak or simply from the tendency of a tire to lose pressure over time. When air pressure gets too low, the tire's sidewalls flex more, and heat builds up within the tire. Excessive air pressure can also distort the shape of the tire, leading to decreased traction and increased wear and tear down the center of the tire. Depending on the circumstances, repeatedly overinflated tires could wear out more quickly. A tire bulges in the center of the tread when You overinflate it.