The Brake System Light is On
If the red or yellow brake light appears on your dashboard, it's a signal that directly threatens your safety on the road. You can't ignore it, as the brake system is a crucial part of your car.
Likely causes — most common first
Low Brake Fluid Level
The fluid often leaks through worn-out brake pads and discs or there's a leak in the brake lines. When there's too little fluid in the reservoir, the sensor signals danger.
Brake Pad Wear
Modern cars have special sensors that wear out with the brake pads or trigger when the pads are too thin. This turns on the warning light.
Problems with the Brake Pad Sensor or Wiring
The wire to the wear sensor can be damaged by stones or branches, and contacts often corrode due to moisture and road salt. This can cause the light to come on even with new brake pads.
The Handbrake is Not Fully Disengaged
The simplest and most common reason: the handbrake lever is not fully lowered or the switch under it is stuck and doesn't see the handbrake is fully released.
Brake Fluid Level Sensor Failure
The float inside the brake fluid reservoir can get stuck or the sensor itself fails, incorrectly showing a low fluid level.
