Denso 234-4473 Oxygen Sensor - Downstream

Denso OE Style Oxygen Sensor 234-4473

Denso 234-4473 is an OE Style heated oxygen sensor built for direct replacement on select BMW applications. It is engineered for a specific fit and threaded mounting, with a 4-wire male connector and a 38.58-inch wiring harness for the listed downstream locations.

Key Features

• Heated oxygen sensor for downstream exhaust monitoring
• Specific-fit design for direct replacement on listed BMW models
• Threaded mounting with 0.708-inch thread diameter
• 4-wire configuration with male connector
• 38.58-inch wiring harness length
• OE Style construction for exact replacement fitment
• Aluminum oxide trap layer helps protect the ceramic element from silicone and lead contamination

Product Details

This Denso oxygen sensor is part of the OE Style line, which focuses on exact replacement dimensions and first-time fitment. It is built and tested to OE standards and uses Denso’s protective trap-layer design to help preserve sensor performance in demanding exhaust conditions. For BMW 325Ci, 325i, 330Ci, 330i, 525i, 530i, and X3 downstream applications, Denso 234-4473 provides the correct sensor format for the listed model years and build notes.

This part cross-references Bosch 15680 and NTK 25658 for the same application.

Vehicle Fitment

• Fits 2003-2006 BMW 325Ci, downstream
• Fits 2004-2006 BMW 330Ci, downstream
• Fits 2004-2006 BMW X3, downstream
• Fits 2003-2005 BMW 325i, downstream
• Fits 2004-2005 BMW 330i, downstream
• Fits 2004-2005 BMW 525i, downstream
• Fits 2004-2005 BMW 530i, downstream
• Fits 2003 BMW 325Ci, downstream, from 3/03; OE Style
• Fits 2003 BMW 325i, downstream, from 3/03; OE Style
• Fits 2003 BMW 330Ci, downstream, from 3/03; OE Style
• Fits 2003 BMW 330i, downstream, from 3/03; OE Style

Installation Notes

Confirm the downstream sensor location before ordering and match the connector, wire count, and thread size to the original unit. On BMW 325Ci, 330i, and X3 applications, verify the build date note for 2003 vehicles marked “from 3/03.” Use proper exhaust sensor removal tools and inspect the harness routing so the lead length matches the factory path.

Quality Assurance

Denso manufactures and tests this sensor to OE standards for consistent replacement performance. The OE Style design is intended to deliver the correct part and fit for the listed BMW applications, with sensor protection features that support long-term durability in exhaust service.