Take the appropriate action and verify that the warning light turns off.

Taking Action
Message Indicated on DisplayMazda 6 Owners Manual: Stopping The Smart Brake Support (SBS) System Operation
The Smart Brake Support (SBS) system can be temporarily deactivated.
When the Smart Brake Support (SBS) system is turned off, the Smart Brake Support
(SBS) OFF indicator light turns on.
When the engine is restarted, the system becomes operational.
NOTE
If the Smart Brake Support (SBS) system ...
Mazda 6 Owners Manual: Thermostat
THERMOSTAT REMOVAL/INSTALLATION
1. Remove the plug hole plate.
2. Disconnect the negative battery cable.
3. Drain the engine coolant. (See COOLING SYSTEM SERVICE WARNINGS.)
4. Remove the drive belt. (See DRIVE BELT REPLACEMENT.)
5. Remove the washer tank.
6. Remove the P/S oil pump.
Note
...