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: Dtc c1955, c1956
Caution When attaching the tester lead to the DSC HU/CM connector the SST (49 G066 004) must be used. Diagnostic procedure ...

Mazda 6 Service Manual: Radio Reception
AM characteristics AM signals bend around such things as buildings or mountains and bounce off the ionosphere. Therefore, they can reach longer distances than FM signals. Because of this, two stations may sometimes be picked up on the same frequency at the same time. FM characteristics An ...