This TSB applies to 2007-2009 Mazda3 (not including Mazdaspeed3) and 2007-2010 Mazda5 vehicles with VINs lower than JM1CR*****367196 produced before November 6, 2009. Some vehicles may experience the MIL on with DTC P0131/P2251 because the A/F sensor connector bracket contacts and damages the sensor harness. To prevent this interference, the shape of the sensor connector bracket has been changed.
DTC P0131: A/F sensor circuit low input
DTC P2251: A/F sensor negative current control circuit open
1. Verify the concern.
2. Inspect the A/F sensor harness for damage
a. If the harness is damaged, bend the sensor harness connector bracket to prevent interference, then replace the A/F sensor with a new one.
b. If the harness is not damaged, this information is not applicable. Refer to MS3 online for troubleshooting procedures.
3. Cover the tips of pliers with vinyl tape to prevent damage to the surface of the bracket.
4. Using the pliers, bend the bracket to make clearance between the harness and the edge of the bracket by 8 mm or more. DO NOT bend the clip to avoid breakage.
REPLACEMENT A/F SENSOR ****-18-8G1