
Diagnostic Procedure

Dtc 21
Dtc 58Mazda 6 Service Manual: Nonreturn valve inspection
1. Remove the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION.)
2. Siphon the fuel from the fuel tank.
Note
Nonreturn valve is integrated in the fuel tank.
The nonreturn valve is normally closed by the spring force.
3. Verify that the nonreturn valve is closed.
If the nonretu ...
Mazda 6 Service Manual: Exhaust system
EXHAUST SYSTEM INSPECTION
Start the engine and inspect each exhaust system component for exhaust gas
leakage.
If leakage is found, repair or replace as necessary.
EXHAUST SYSTEM REMOVAL/INSTALLATION
Warning
When the engine and exhaust system are hot, they can badly burn.
Turn off t ...