Some vehicles use an electronic brake pad wear sensor that lights a dashboard warning when the pads get low. After you replace the pads, that light needs to go out - and how it does depends on your car. Here is what to know.
How electronic wear sensors work
Unlike the mechanical squealer tab that just squeals, an electronic sensor is a small wire loop in the pad. When the pad wears down far enough, the rotor grinds through the loop, breaking the circuit and lighting a brake wear warning - see brake pad wear sensors. It is a genuine low-pad alert, not a fault.
Replace the sensor with the pads
Because the sensor is destroyed when it triggers, you must fit a NEW wear sensor along with the new pads - many pad sets include one. Reusing a worn (broken) sensor leaves the warning on. Installing a fresh, intact sensor restores the circuit, which is what allows the light to clear.
How the light turns off
On many cars, once a new intact sensor is fitted the light simply goes out after you turn the ignition on, or after a short drive as the system re-checks the circuit. Some vehicles need a scan-tool reset or a menu reset in the dash. Check your owner's manual for your specific model's procedure.
If the light stays on
A light that stays on after new pads and sensor usually means the sensor was pinched, not connected, or the wrong one - re-check the install. If it persists, a scan tool will show whether the circuit reads intact. Always fit quality pads with the correct sensor and fresh hardware.