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: Oil cooler flushing
Note
The contaminated cooler line (oil pipes and hoses) and auxiliary
cooler must be flushed completely when ATX is overhauled or replaced.
1. Remove the two oil cooler line hoses and apply air pressure of 196 kPa
{2.0 kgf/cm2, 28 psi} from the return hose (pipe) side.
Caution
Power ...
Mazda 6 Service Manual: Illuminated Entry System
When the illuminated entry system operates, the overhead lights, the courtesy
lights, and an ambient light* turn on in the following conditions:
The driver's door is unlocked after the ignition is switched OFF.
The ignition is switched OFF with all doors closed.
NOTE
(Overhead lights) ...