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: Heated oxygen sensor (ho2s) inspection
HO2S Voltage Inspection Note Perform the following inspection only when directed. 1. Warm up the engine and run it at idle. 2. Disconnect the HO2S connector. 3. Connect the voltmeter test leads to the following HO2S terminals: HO2S (front and rear) - (+) leadterminal A - (-) le ...

Mazda 6 Service Manual: Locking, Unlocking with Auxiliary Key
Turn the auxiliary key toward the front to lock, toward the back to unlock. To lock All doors lock automatically when the driver's door is locked using the auxiliary key. To unlock The driver’s door unlocks when the auxiliary key is turned briefly to the unlock position and then immediatel ...