BDFHYK Oxygen Sensor Upstream Downstream O2, Compatible with Chevrolet Astro Avalanche 1500 C1500 C2500 K1500 K2500 Compatible with GMC K1500 K2500 P3500 Savana 1500, 234-4012, Replacement 1PCS

This BDFHYK 234-4012 O2 sensor is an OE-style aftermarket replacement for listed Chevrolet Astro, Avalanche 1500, C1500, C2500, K1500, K2500 and GMC K1500, K2500, P3500, Savana 1500 applications. The exact upstream or downstream location varies by application. Before ordering, match the original sensor number and confirm year, engine, emissions configuration, connector, wiring, lead length and exhaust position. A stored diagnostic code alone does not prove oxygen sensor failure.

234-4012 O2 Sensor Fitment for Chevrolet and GMC Applications

• Chevrolet Astro, Avalanche 1500, C1500, C2500, K1500 and K2500
• GMC K1500, K2500, P3500 and Savana 1500

Confirm the exact year and engine before ordering because these vehicle families span multiple powertrain and emissions configurations.

234-4012 O2 Sensor Interchange References

Replacement references include 234-4012, 19178918, 19178930, 19178937, 19178961, 25315809, 8251653130, 8253121880, 8253122000, 8253252660 and 96335927.

234-4012 Upstream and Downstream Position Check

Position is application-dependent. Do not assign one universal upstream, downstream or Bank/Sensor location without service information for the exact vehicle and engine.

234-4012 O2 Sensor Diagnosis Before Replacement

Inspect the connector, wiring, heater circuit, related fuse, exhaust leaks, intake or vacuum leaks, fuel pressure, injector operation, misfires and catalyst condition before replacement. Fuel-trim and catalyst-efficiency codes require system diagnosis.

234-4012 O2 Sensor Installation Notes

• Allow the exhaust system to cool before service.
• Use an O2 sensor socket or suitable wrench.
• Compare the connector, lead length and original number 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 safely.

234-4012 O2 Sensor Package Contents

• 1 × BDFHYK oxygen sensor

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