If there is the possibility of a collision with a vehicle ahead, the beep sounds continuously and a warning is indicated in the multi-information display and the active driving display.

Smart Brake Support (SBS) (Some models)
Stopping The Smart Brake Support (SBS) System OperationMazda 6 Owners Manual: Instrument cluster input/output check mode
Note
In this mode, it is possible to check the items in the following
chart.
Diagnostic Trouble Code Chart
Note
Diagnostic trouble codes which are not listed may be indicated,
but they cannot be inspected.
The diagnostic trouble codes are displayed in numerical order.
(While ...
Mazda 6 Owners Manual: Cruise control switch inspection
1. Disconnect the negative battery cable.
2. Remove the driver-side air bag module. (See DRIVER-SIDE AIR BAG MODULE
REMOVAL/INSTALLATION.)
3. Disconnect the cruise control switch connector.
4. Inspect for resistance and continuity between the cruise control switch
terminals using an ohmmeter. ...