Denso 234-4279 Oxygen Sensor - Downstream
OE Quality 60-Day Returns
Denso
 OE Style

Denso 234-4279 Oxygen Sensor - Downstream

Brand Denso 234-4279
Position Downstream
Connector Gender Male
Mounting Type Threaded
Sensor Type Heated
Thread Diameter 0.708
Universal Or Specific Fit Specific
Wire Quantity 4
Wiring Harness Length 34.84
Product line OE Style
Fits Mazda · 5 vehicles

OE-style replacement. Precision-built for exact replacement and a first-time fit.

Heated sensor. Helps support faster operation and efficient engine performance.

Threaded mounting. Specific-fit design with a male connector and 4-wire harness.

Cross-references Bosch 18120, Mazda L51918861B and Mazda L51918861C for the same application. See all 6.

$88.02Free shipping
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Order total $88.02
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Free returns within 60 days if it doesn't fit when fitment is verified.
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Denso OE Style Oxygen Sensor for Mazda 6

Denso 234-4279 is an OE Style heated oxygen sensor built for direct replacement on select Mazda 6 applications. It is engineered for the downstream position on 2009-2013 Mazda 6 models and uses a specific-fit, threaded design for accurate sensor placement and reliable exhaust monitoring.

Key Features

  • OE Style replacement oxygen sensor for direct-fit service
  • Heated sensor design for faster operating response
  • Specific fit for the downstream position
  • 4-wire configuration with male connector
  • Threaded mounting with 0.708 in. thread diameter
  • 34.84 in. wiring harness length for application-specific routing

Product Details

This Denso oxygen sensor is manufactured and tested to OE standards for precise replacement fitment and dependable performance. The sensor uses Denso’s aluminum oxide trap layer to help protect the ceramic element from silicone and lead contamination, supporting stable engine management and consistent exhaust feedback. Part number 234-4279 is a direct replacement choice for drivers servicing a Mazda 6 downstream oxygen sensor concern.

This part cross-references Bosch 18120 for the same application.

Used For

  • Check engine light concerns related to downstream oxygen sensor performance
  • Incorrect air-fuel ratio feedback from the exhaust system
  • Reduced fuel economy caused by a failing oxygen sensor
  • Slow or inaccurate sensor response during emissions monitoring
  • Replacement of a worn or contaminated Mazda 6 oxygen sensor

Installation Notes

Fits 2009-2013 Mazda 6, downstream. Confirm the connector style, wire count, and threaded mounting location before installation. Use the vehicle’s original routing path for the 34.84 in. harness and verify the sensor is installed in the correct downstream exhaust position. Part number 234-4279 is a specific-fit sensor, so matching the application details is important for proper operation.

Quality Assurance

Denso manufactures this OE Style oxygen sensor to strict original-equipment standards and tests each component for replacement accuracy and fit. The design focuses on first-time fitment and long-term resistance to contamination for dependable service on Mazda 6 applications.

Related reading

This part fits 5 vehicles
Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.
YearMakeModelPositionNotes
2013Mazda6DownstreamOE Style
2012Mazda6DownstreamOE Style
2011Mazda6DownstreamOE Style
2010Mazda6DownstreamOE Style
2009Mazda6DownstreamOE Style
Directly replaces or cross-references 6 part numbers
Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.
Bosch — 18120Mazda — L51918861BMazda — L51918861CNTK — 22129Walker Products — 250-24859Walker Products — 350-34520