Some 2007-2009 Mazda3 (not including Mazdaspeed3) and 2007-2010 Mazda5 vehicles with VINs lower than JM1CR******367196 (produced before November 6, 2009 may experience the MIL on with DTC P0131/P2251 because the A/F sensor connector bracket contacts and damages the sensor harness. To prevent the interference, the shape of the sensor connector bracket has been changed.
DTC P0131: A/F sensor circuit low input
DTC P02251: A/F sensor negative current control circuit open.
- Verify the concern.
- Inspect the A/F sensor harness for damage.
- If the harness is damaged, bend the sensor harness connector bracket according to the following steps to prevent interference, then replace the A/F sensor with a new one.
- If the harness is not damaged, this bulletin does not apply. Refer to MS3 online for troubleshooting procedure.
- Cover the tips of pliers with vinyl tape to prevent damage and to prevent risk of future rust to the surface of the bracket.
- Using the pliers, bend the bracket to make the clearance between the harness and the edge of the bracket 8mm or more. Do not bend the clip to avoid breakage.
- Verify the repair.
Bend the bracket (A) to create an 8mm clearance between the harness (B) and the edge of the bracket. Avoid bending the clip (C).