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: Engine Start Function When Key Battery is Dead
CAUTION When starting the engine by holding the transmitter over the push button start due to a dead key battery or a malfunctioning key, be careful not to allow the following, otherwise the signal from the key will not be received correctly and the engine may not start. Metal parts of ot ...

Mazda 6 Service Manual: Transaxle fluid temperature (tft) sensor inspection
On-Vehicle Inspection 1. Disconnect the negative battery cable. 2. Remove the air cleaner component. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION.) Caution Water or foreign objects entering the connector can cause a poor connection or corrosion. Be sure not to drop water or foreign object ...