Denso 234-4877 Oxygen Sensor - Downstream or Downstream Right

Denso OE Style Oxygen Sensor 234-4877

Denso 234-4877 is an OE Style heated oxygen sensor built for specific BMW applications. It is engineered for exact replacement fitment and consistent signal performance in downstream locations on select 2006-2010 BMW 550i and 650i models, plus additional 2006-2009 BMW 323i and 2006-2008 BMW 750i and 750Li applications.

Key Features

• Heated oxygen sensor with specific-fit design
• OE Style replacement for direct installation in the original mounting location
• 4-wire configuration with female connector
• Threaded mounting type with 0.708 in. thread diameter
• 17.13 in. wiring harness length for proper routing
• Built to Denso OE standards for replacement accuracy
• Aluminum oxide trap layer helps protect the ceramic element from silicone and lead contamination

Product Details

Denso OE Style part number 234-4877 is designed for BMW exhaust systems that require a downstream heated oxygen sensor. The sensor is precision built for first-time fitment and is intended to restore accurate exhaust feedback in the engine management system. This part cross-references BMW 11787539126 and Bosch 16794 for the same application. It is a direct replacement choice for BMW 550i, BMW 650i, BMW 323i, BMW 750i, and BMW 750Li vehicles listed in the fitment data.

What It Helps Address

• Check engine light related to oxygen sensor performance
• Incorrect air-fuel feedback from a worn downstream sensor
• Reduced fuel economy caused by inaccurate exhaust readings
• Slow or inconsistent sensor response in heated O2 sensor circuits
• Fitment issues from using a universal sensor instead of a specific replacement

Installation Notes

Verify the connector style, wire count, thread diameter, and downstream position before installation. This sensor uses a threaded mount and a female connector, so it should be matched to the original BMW harness and exhaust bung location. Confirm the vehicle application by year, model, and sensor position before ordering. For BMW 550i and BMW 650i applications, this part is listed for the downstream right position; for BMW 323i, 525i, 525xi, 530i, and 530xi applications, it is listed for downstream use on cylinder 1, 2, and 3 configurations.

Quality Assurance

Denso manufactures and tests this oxygen sensor to OE standards for replacement accuracy and consistent performance. The OE Style line is built for exact fit and includes contamination protection at the sensing element to support long service life in demanding exhaust conditions.

Compatible With

• Fits 2006-2010 BMW 550i, Downstream Right
• Fits 2006-2010 BMW 650i, Downstream Right
• Fits 2006-2009 BMW 323i, Downstream
• Fits 2006-2008 BMW 750i, Downstream Right
• Fits 2006-2008 BMW 750Li, Downstream Right
• Fits 2006-2007 BMW 525i, Downstream
• Fits 2006-2007 BMW 525xi, Downstream
• Fits 2006-2007 BMW 530i, Downstream
• Fits 2006-2007 BMW 530xi, Downstream