Faulty Brake Fluid Level Sensor: If the brake fluid level is adequate but the warning light remains on, the brake fluid level sensor may be faulty. This sensor monitors brake fluid level and triggers the warning light when it drops too low.
Worn Brake Pads: Even though you mentioned the brake pads are fine, it's still worth inspecting them. Look for uneven wear, cracks, or thin brake pad material. Worn brake pads can cause the brake warning light to illuminate.
ABS System Issues: The Anti-lock Braking System (ABS) may have a fault. The ABS system works in conjunction with the brakes and helps prevent wheels from locking up during braking. If the ABS system malfunctions, it can trigger the brake warning light.
Electrical Issues: A short circuit, faulty wiring, or a problem with the brake light switch can also cause the warning light to stay on.
If you've inspected all of the above and still can't find the cause, it's best to have your BMW diagnosed by a professional.
