For each gear position while in the manual mode, the speed limit is set as follows: When the selector lever is operated within the range of the speed limit, the gear is shifted.

Shift up
The gear does not shift up while the vehicle speed is lower than the speed limit.
Shift down
The gear does not shift down while the vehicle speed exceeds the speed limit.
If the vehicle speed exceeds the speed limit and the gear does not shift down, the gear position indication flashes 2 times to notify the driver that the gear cannot be shifted.
Kickdown
When the accelerator pedal is depressed fully while driving, the gear shifts down.
However, the gears do not kickdown while the DSC is turned off.
NOTE
The gear also shifts down using kickdown while in the second gear fixed mode.
Auto-shift down
The gear shifts down automatically depending on the vehicle speed during deceleration.
NOTE
If the vehicle comes to a stop while in the second gear fixed mode, the gear remains in second.
Second Gear Fixed Mode
Recommendations for ShiftingMazda 6 Owners Manual: Cargo compartment light switch inspection
1. Remove the liftgate lower trim. (See LIFTGATE LOWER TRIM
REMOVAL/INSTALLATION)
2. Disconnect the cargo compartment light switch connector.
3. Inspect for continuity between the cargo compartment light switch
terminals using an ohmmeter.
If not as specified, replace the liftgate lock.
...
Mazda 6 Owners Manual: Selector cable adjustment
1. Remove the center console.
2. Shift the selector lever to P position.
3. Unlock the lock piece of the selector cable (selector lever side) in the
order shown in the figure.
4. Verify that the manual shaft is in P position.
5. Lock the lock piece of the selector cable (selector lever side) ...