1. Disconnect the negative battery cable.
2. Remove the intake maniforld.(see INTAKE-AIR SYSTEM REMOVAL/INSTALLATION.)
3. Remove the PCV valve.
4. Blow through the valve and verify that air flows as specified.

Specification

Egr valve inspection
Three-way catalytic converter (twc) inspectionMazda 6 Service Manual: Active Adaptive Shift (AAS)
Active Adaptive Shift (AAS) automatically controls the transaxle shift points
to best suit the road conditions and driver input. This improves driving feel. The
transaxle may switch to AAS mode when driving up and down slopes, cornering, driving
at high elevations, or depressing the accelerato ...
Mazda 6 Service Manual: Add-On Non-Genuine Parts and Accessories
Non-genuine parts and accessories for Mazda vehicles can be found in stores.
These may fit your vehicle, but they are not approved by Mazda for use with Mazda
vehicles. When you install non-genuine parts or accessories, they could affect your
vehicle's performance or safety systems; the Mazda w ...