1. Remove the drive belt. (See DRIVE BELT REPLACEMENT.)
2. Verify that the drive belt auto tensioner moves smoothly in the operational direction.

3. Turn the drive belt auto tensioner pulley by hand and verify that it rotates smoothly.
4. Install the drive belt. (See DRIVE BELT REPLACEMENT.)
Drive belt replacement
Valve clearanceMazda 6 Service Manual: Dual proportioning valve replacement (without abs)
1. Remove in the order indicated in the table.
2. Install in the reverse order of removal.
Dual Proportioning Valve Installation Note
Install the dual proportioning valve so that the R mark faces the left side
of the vehicle.
...
Mazda 6 Service Manual: Transaxle range (tr) switch removal/installation
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 objects on the
connector w ...