The mirror defoggers defrost the outside mirrors.
The mirror defoggers operate in conjunction with the rear window defogger.
To turn on the mirror defoggers, switch the ignition ON and press the rear window defogger switch.
Manual Climate Control

Fully Automatic Climate Control

Rear Window Defogger
HornMazda 6 Owners Manual: Instrument cluster inspection
Speedometer
Using the input/output check mode
Inspect the speedometer by setting it in the input/output check mode DTC 12.
Using a speedometer tester
1. Adjust the tire air pressure to the specification.
2. Using a speedometer tester, verify that the speedometer indication is
within the allow ...
Mazda 6 Owners Manual: Dtc clearing procedure
1. Start the on-board diagnostic test mode.
2. First press the POWER button, then simultaneously press AUDIO CONT button
for 2 seconds or more.
Caution
Before clearing the DTCs, be sure to enter all of them displayed
in the on-board diagnostic test mode in the Audio Repair Order Form. ...