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: Shift-Lock System
The shift-lock system prevents shifting out of P unless the brake pedal is depressed. To shift from P: 1. Depress and hold the brake pedal. 2. Start the engine. 3. Press and hold the lock-release button. 4. Move the selector lever. NOTE When the ignition is switched to ACC or the ignition ...

Mazda 6 Service Manual: Knock sensor inspection
Note Perform the following test only when directed. Resistance Inspection 1. Turn the ignition switch to LOCK. 2. Disconnect the knock sensor connector. 3. Measure the resistance between the knock sensor terminals A and B using an ohmmeter. If not as specified, replace the knock sens ...