BDFHYK Oxygen Sensor Upstream Downstream O2, Compatible with Ford E-150 E-250, Compatible with Mercury Mariner Milan, 18124, ZZC318861 Replacement 1PCS

This BDFHYK O2 sensor is an OE-style aftermarket replacement for verified Ford, Lincoln, Mazda, and Mercury applications that cross-reference 18124 and ZZC318861. Sensor position varies by application, so confirm the exact year, engine, original sensor number, exhaust location, connector, wiring layout, lead length, and emissions configuration before ordering. Do not select by vehicle name or upstream/downstream wording alone. A Check Engine Light or stored OBD-II code does not by itself confirm oxygen sensor failure.

18124 O2 Sensor Fitment for Ford, Lincoln, Mazda and Mercury

18124 O2 Sensor Interchange References

Replacement references include 18124 and ZZC318861. Confirm the number together with the exact vehicle, engine, connector, and exhaust location.

18124 Sensor Position Check by Application

The verified cross-fit for this part includes different sensor positions depending on the vehicle and engine. Do not assign a universal upstream, downstream, Bank 1 Sensor 1, or Bank 1 Sensor 2 position. Match the removed sensor and vehicle-specific service information.

18124 O2 Sensor Diagnosis Before Replacement

Inspect the connector, wiring, heater circuit, related fuse, power and ground, exhaust leaks, intake or vacuum leaks, fuel pressure, injector faults, misfires, and catalyst operation before replacement. Fuel-trim and catalyst-efficiency codes require diagnosis rather than automatic sensor replacement.

18124 O2 Sensor Installation Notes

• Allow the exhaust system to cool before service.
• Use an O2 sensor socket or suitable wrench.
• Compare the replacement connector, lead length, and reference number with the removed sensor.
• Inspect the bung threads and start the sensor by hand.
• Use anti-seize only when permitted by the sensor instructions.
• Tighten to the applicable vehicle service specification and route the harness safely.

18124 O2 Sensor Package Contents

• 1 × BDFHYK oxygen sensor

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