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 InspectionKeyless Entry System
This system uses the key buttons to remotely lock and unlock the doors and the
liftgate.
The system can start the engine without having to take the key out of your purse
or pocket.
It can also help you signal for attention.
Operating the theft-deterrent system is also possible on theft-deterr ...
Customer Assistance (Puerto Rico)
Your complete and permanent satisfaction is our business. That is why all Authorized
Mazda Dealers have the knowledge and the tools to keep your Mazda vehicle in top
condition.
If you have any questions or recommendations for improvement regarding the service
of your Mazda vehicle or servicin ...
Charging System Warning Light
Purpose, Function
Warns the driver of a charging system malfunction.
Construction
The charging system warning light is built into the instrument cluster..
Operation
Illuminates when a malfunction occurs in the charging system and DTCs is
stored in the PCM.
...