1. Disconnect the brake fluid level sensor connector from the master cylinder.
2. Inspect for continuity according to fluid level between the brake fluid level sensor terminals.

If not as indicated in the table, replace the reserve tank..

Brake Switch InspectionClutch Pedal Removal/Installation [C66 M R]
CAUTION:
Secure the steering wheel using tape or a cable to prevent the steering shaft
from rotating after disconnecting the steering shaft. If the steering wheel
rotates after the steering shaft and the steering gear and linkage are disconnected,
the internal parts of the clock spr ...
Rear End Panel Installation [Panel Replacement]
Symbol Mark
Installation Procedure
1. When installing new parts, measure and adjust the body as necessary to conform
with standard dimensions.
2. Drill holes for the plug welding before installing the new parts.
3. After temporarily installing new parts, make sure the related parts fit p ...
Brake
Brake System
Foot Brake
Your Mazda has power-assisted brakes that adjust automatically through normal
use.
Should power-assist fail, you can stop by applying greater force than normal
to the brake pedal. But the distance required to stop will be greater than usual.
WARNING
Do not coast wi ...