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 InspectionRear Door Garnish Removal/Installation
WARNING:
Using a utility knife with bare hands can cause injury. Always wear gloves
when using a utility knife.
Front
1. Using a tape-wrapped fastener remover, remove clips A in the direction of
arrow (1), (2) shown in the figure.
2. Remove the double-sided adhesive tape in the ...
Warning/Indicator Lights
Warning (Display Indication)
Message information such as system operations or malfunctions is indicated in
the display. Check the vehicle condition or have the vehicle inspected at an Authorized
Mazda Dealer according to the indication.
Brake System Warning Light
This warning has th ...
Engine Coolant
Inspecting Coolant Level
WARNING
Do not use a match or live flame in the engine compartment. DO NOT ADD COOLANT
WHEN THE ENGINE IS HOT:
A hot engine is dangerous. If the engine has been running, parts of the engine
compartment can become very hot. You could be burned.
Carefully inspect the e ...