Diagnostic procedure
Mazda 6 Service Manual: No.4 air intake mode does not change
When performing an asterisked (*) troubleshooting inspection, shake the
wiring harness and connectors while performing the inspection to discover
whether poor contact points are the cause of any intermittent malfunctions.
If there is a problem, check to make sure connectors, terminal ...
Mazda 6 Service Manual: Fuel pump unit inspection
Caution
It is normal to hear the fuel pump operating when the ignition
switch is turned to the ON position.
Note
To improve startability, the fuel pump control operates the fuel
pump unit when the ignition switch is turned to the ON position. Due to
this, fuel pressure is rapidly ...