Move the signal lever down (for a left turn) or up (for a right turn) to the stop position. The signal will self-cancel after the turn is completed.
If the indicator light continues to flash after a turn, manually return the lever to its original position.

The turn signal indicators in the instrument cluster flash according to the operation of the turn signal lever to show which signal is working.

NOTE
Turn and Lane-Change Signals
Lane-Change Signals and Three-Flash Turn SignalMazda 6 Owners Manual: Dtc c1145, c1155, c1165, c1175
Caution
When attaching the tester lead to the DSC HU/CM connector the SST
(49 G066 004) must be used.
Diagnostic procedure
...
Mazda 6 Owners Manual: Nonreturn valve inspection
1. Remove the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION.)
2. Siphon the fuel from the fuel tank.
Note
Nonreturn valve is integrated in the fuel tank.
The nonreturn valve is normally closed by the spring force.
3. Verify that the nonreturn valve is closed.
If the nonretu ...