Mazda 6 Service Manual: No.20 noise occurs at idle when vehicle is stopped in all positions/ranges

No.19 excessive shift shock on torque converter clutch (tcc)

No.21 noise occurs at idle when vehicle is stopped in d, s, l ranges, or in r position

Other materials:

Mazda 6 Service Manual: Service cautions
HANDLING INSUFFICIENT REFRIGERANT LEVEL If an insufficient refrigerant level is detected at troubleshooting, do not charge (add) the refrigerant. Because an accurate amount of refrigerant cannot be determined from the pressure indicated on the manifold gauge, never charge the refrigeran ...

Mazda 6 Service Manual: Supplemental Restraint System Components
(With Front Passenger Occupant Classification System) (Without Front Passenger Occupant Classification System) Driver/Front passenger inflators and air bags Roll-over sensor (some models), crash sensors, and diagnostic module (SAS unit). Seat belt pretensioners Front air bag sensor ...