For older cars and trucks, brake pad manufacturers often put a hard metal tab on one of the pads so that, when the pad wears down enough, the metal tab scrapes against the rotor—and an oh-so-subtle “SCCCRREEEEEEEEEECH” is your reminder that you need new brake pads.
But nowadays, many newer vehicles have a slightly more elegant solution. These brake systems use a small electrical sensor secured to the back of the pad. When your pad material wears down enough for the sensor leads to make contact with the rotor, a polite reminder light appears on your dash. (Where’s the fun in that?)
If you’ve got one of these fancy new rides with a brake pad wear sensor and are confronted with a brake warning light, this helpful video from the brake gang over at PowerStop will help you understand how to service the sensor. And don’t panic—working with brake pads featuring wear sensors like this isn’t any more complicated than the ones you’re used to. Watch this video and see for yourself:
Good article on brake pads sensor