
Diagnostic procedure

Dtc b1231
Dtc b1869, b1870Mazda 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: Noise filter inspection
Brake Light Noise Filter
1. Inspect for resistance and continuity between the noise filter terminals
using an ohmmeter.
If not as specified, replace the noise filter.
Rear Window Defroster Noise Filter
Inspect for resistance and continuity between the noise filter terminals
using an ...