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 b1318
Caution When attaching the tester lead to the ABS (ABS/TCS) HU/CM harness connector, the SST (49 G066 001) must be used. (See ABS (ABS/TCS) HU/CM INSPECTION.) Diagnostic procedure ...

Mazda 6 Service Manual: Steering wheel and column inspection
Steering Wheel Play Inspection With the wheels in the straight-ahead position, gently turn the steering wheel to the left and right and verify that the play is within the specification. If the play exceeds the specification, either the steering joints are worn or the backlash of the stee ...