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
3. To stop the on-board diagnostic test mode, turn the ignition switch to the LOCK position.
Supplier identification procedure
Dtc tableMazda 6 Service Manual: Starting procedure for on-board diagnostic test mode
Note
All DTCs displayed in the on-board diagnostic test mode should be
entered in the Audio Repair Order Form.
1. Turn the ignition switch to the ACC or ON position.
2. First press the POWER button, then simultaneously press the AM button and
TAPE/MD button for 2 seconds or more.
N ...
Mazda 6 Service Manual: Heater core inspection
1. Remove the A/C unit. (See A/C UNIT REMOVAL/INSTALLATION.)
2. Remove the heater core from the A/C unit.
3. Inspect for cracks, damage, and coolant leakage.
If any problems are found, replace the heater core.
4. Inspect for bent fins.
If any are bent, use a flathead screwdriver to stra ...