BDFHYK Oxygen Sensor Downstream O2, Compatible with Mazda 3 5 3 Sport l4 2.5L, 18140, L5D91886ZC Replacement 1PCS

This BDFHYK 18140 downstream O2 sensor is an OE-style aftermarket replacement for listed Mazda 3, Mazda 5 and Mazda 3 Sport 2.5L L4 applications that cross-reference L5D91886ZC. Before ordering, confirm the exact model year, 2.5L engine, original sensor number, downstream exhaust location, connector, wiring layout, lead length and emissions configuration. Similar Mazda models can use different sensors by year or exhaust position, so the removed sensor should be compared before installation.

18140 Downstream O2 Sensor Fitment for Mazda 2.5L Applications

• Mazda 3 — listed 2.5L L4 application
• Mazda 5 — listed 2.5L L4 application
• Mazda 3 Sport — listed 2.5L L4 application

Confirm the exact year and emissions configuration before ordering.

18140 O2 Sensor Interchange References

Replacement references include 18140 and L5D91886ZC. Verify the original number together with the connector and downstream position.

18140 Downstream Sensor Position Check

This SKU is listed for downstream use. Do not infer a universal Bank 1 Sensor 2 or Bank 2 Sensor 2 label without service information for the exact vehicle.

18140 O2 Sensor Diagnosis Before Replacement

Inspect wiring, connector condition, heater circuit, related fuse, exhaust leaks, fuel-control faults, misfires and catalyst operation before replacement. A Check Engine Light or catalyst-efficiency code alone does not identify the sensor as failed.

18140 O2 Sensor Installation Notes

• Allow the exhaust system to cool before service.
• Use an O2 sensor socket or suitable wrench.
• Compare the connector and lead length with the removed sensor.
• Inspect bung threads and start the sensor by hand.
• Use anti-seize only when permitted by the sensor instructions.
• Tighten to the applicable service specification and route the harness away from heat and moving parts.

18140 O2 Sensor Package Contents

• 1 × BDFHYK oxygen sensor

Important: This is an OE-style aftermarket replacement, not a factory-branded part.