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: Smart Brake Support (SBS) (Some models)
The Smart Brake Support (SBS) system alerts the driver of a possible collision using a display and warning sound if the radar sensor (front) and the Forward Sensing Camera (FSC) determine that there is the possibility of a collision with a vehicle ahead while the vehicle is being driven at abo ...

Mazda 6 Service Manual: Rear door speaker inspection
1. Inspect for resistance between the rear door speaker terminals using an ohmmeter. If not as specified, replace the rear door speaker. 2. To verify that the rear door speaker outputs sound, apply voltage to the rear door speaker and release using a 1.5-V battery. If not outputs ...