Walker 350-34673 Oxygen Sensor - Downstream
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Walker
 Walker Products Aftermarket

Walker 350-34673 Oxygen Sensor - Downstream

Brand Walker 350-34673
Position Downstream
Connector Gender Female
Overall Length 22.76
Sensor Type Heated
Thread Diameter 18.00
Universal Or Specific Fit Specific
Wire Gauge Measurement 20
Wire Quantity 4
Wiring Harness Length 19.21
Product line Walker Products Aftermarket
Fits BMW · 64 vehicles

OE replacement. Engineered to match original equipment sensor requirements.

Heated sensor. Delivers faster feedback for accurate engine management.

Specific fit. Built for the exact application, not a universal install.

$87.48Free shipping
In stock · usually ships same day before 1pm CST
Step 1 — Confirm fitment
Free return shipping if it doesn't fit when you check fitment here first.

Select your vehicle to confirm fitment
Verify this part fits before purchasing — free returns if it doesn't
Step 2 — Quantity
Order total $87.48
Free shipping to the continental U.S.
Free returns within 60 days if it doesn't fit when fitment is verified.
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Walker 350-34673 Oxygen Sensor for BMW

Walker Products 350-34673 is a heated oxygen sensor built as an OE-style replacement for specific BMW downstream applications. It is engineered for direct fitment, accurate ECU feedback, and reliable emissions-system monitoring on supported vehicles.

Key Features

  • Heated oxygen sensor for downstream placement
  • Specific fit design for selected BMW applications
  • 4-wire configuration with female connector
  • 19.21 in. wiring harness length and 22.76 in. overall length
  • 18.00 mm thread diameter
  • 20-gauge wiring for the sensor harness

Product Details

Walker Products Aftermarket focuses on engine management and oxygen/air-fuel sensors developed as replacement parts for original equipment applications. Part number 350-34673 is built for downstream use and is listed for BMW models including 2016-2021 740i, 2017-2021 M240i, 2017-2020 440i, 2017-2020 540i, and 2018-2020 X3, along with additional supported BMW fitments. This sensor is intended to restore proper diagnostic feedback to the ECU when the original unit is worn or failing.

This part cross-references Monroe Shocks & Struts (e.g., 172286, 182286) for the same application.

What It Helps Address

  • Check engine light related to oxygen sensor performance
  • Poor fuel economy caused by incorrect exhaust feedback
  • Rough engine operation tied to faulty emissions data
  • Elevated exhaust emissions from a degraded downstream sensor
  • Stored ECU fault codes linked to the affected sensor circuit

Installation Notes and Tips

Verify the vehicle’s downstream bank and sensor position before ordering. For BMW applications such as M240i, 440i, 540i, 740i, and X3, confirm the connector style, thread size, and harness routing match the original sensor. Inspect the wiring harness and connector for heat damage, abrasion, or corrosion before installation, since physical damage can shorten sensor life.

Quality Assurance

Walker Products states that its engine management sensors are developed as OE replacement parts and manufactured under Automotive ISO9001/TS 16949 quality systems. The brand has supplied engine management and fuel system components since 1946.

Related reading

This part fits 64 vehicles
Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.
YearMakeModelSubmodelLitersCylindersFuel TypePositionNotes
2021BMWM240i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2021BMWM240i xDrive—3.0LL6—DownstreamOE Replacement
2021BMWX3—3.0LL6—DownstreamOE Replacement
2021BMWX4—3.0LL6—DownstreamOE Replacement
2020BMW440i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2020BMW440i Gran Coupe—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2020BMW440i xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2020BMW440i xDrive Gran Coupe—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2020BMW540i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2020BMW540i xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2020BMW740i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2020BMW740i xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2020BMWM240i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2020BMWM240i xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2020BMWX3M40i3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2020BMWX4M40i3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2019BMW340i GT xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2019BMW440i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2019BMW440i Gran Coupe—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2019BMW440i xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2019BMW440i xDrive Gran Coupe—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2019BMW540i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2019BMW540i xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2019BMW640i xDrive Gran Turismo—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2019BMW740i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2019BMW740i xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2019BMWM140i—3.0LL6—DownstreamOE Replacement
2019BMWM240i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2019BMWM240i xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2019BMWX3M40i3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2019BMWX4—3.0LL6—DownstreamOE Replacement
2018BMW340i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2018BMW340i GT xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2018BMW340i xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2018BMW440i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2018BMW440i Gran Coupe—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2018BMW440i xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2018BMW440i xDrive Gran Coupe—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2018BMW540i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2018BMW540i xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2018BMW640i xDrive Gran Turismo—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2018BMW740i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2018BMW740i xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2018BMWM140i—3.0LL6—DownstreamOE Replacement
2018BMWM240i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2018BMWM240i xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2018BMWX3—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2017BMW340i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2017BMW340i GT xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2017BMW340i xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2017BMW440i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2017BMW440i Gran Coupe—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2017BMW440i xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2017BMW440i xDrive Gran Coupe—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2017BMW540i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2017BMW540i xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2017BMW740i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2017BMW740i xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2017BMWM140i—3.0LL6—DownstreamOE Replacement
2017BMWM240i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2017BMWM240i xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2016BMW340i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2016BMW340i xDrive—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket
2016BMW740i—3.0LL6GASDownstreamFits downstream bank 1 sensor 2 on specific vehicle models.; Walker Products Aftermarket