Bosch 17425 Oxygen Sensor - Downstream

Bosch Wideband Oxygen Sensor for BMW Diesel Applications

Bosch 17425 is an Actual OE wideband air-fuel oxygen sensor built for precise mixture feedback in modern engine management systems. It is a heated, specific-fit sensor with a 40.2 in wire length and 5-wire harness design for direct replacement service on select BMW diesel applications.

For BMW 328d, BMW 328d xDrive, and BMW X3 downstream applications, this Bosch oxygen sensor provides the detailed lambda measurement the ECU needs for accurate fuel control and emissions monitoring. Bosch 17425 is engineered with a threaded metal housing, oblong male connector, and OE-style harness layout for a factory-style replacement.

Key Features

• Wide-band oxygen sensor for continuous air-fuel ratio measurement
• Heated design for faster sensor operation after startup
• Specific-fit replacement with OE-style connector and harness
• Metal housing with threaded mounting for secure installation
• 18 mm thread diameter and 22 mm hex size
• 36.8 in harness length and 40.2 in overall wire length
• Bosch Actual OE Oxygen Sensor line for OE-proven application coverage

Product Details

Bosch pioneered the wideband A/F oxygen sensor design used in modern engine management, and part number 17425 reflects that OE development background. The sensor measures across the full lambda range, giving the ECU more detailed feedback than a traditional switching sensor. That level of signal detail supports accurate air-fuel control under changing load and temperature conditions, which is especially important on downstream BMW diesel emissions systems. This part cross-references Monroe Shocks & Struts (e.g., 172286, 182286) for the same application.

What This Sensor Helps Address

• Fault codes related to downstream oxygen sensor performance
• Inaccurate air-fuel ratio feedback to the ECU
• Rough emissions monitoring behavior after sensor aging
• Delayed sensor response during cold start or thermal cycling
• Driveability issues tied to degraded wideband signal output

Installation Notes and Tips

Fits 2014-2017 BMW 328d, downstream. Fits 2014-2017 BMW 328d xDrive, downstream. Fits 2015-2017 BMW X3, downstream. Confirm connector shape, thread size, and sensor position before installation. Use the existing harness routing and verify the downstream location matches the original sensor placement on the vehicle.

Quality Assurance

Bosch backs this oxygen sensor with more than five decades of OE development experience and a product line supplied to vehicle manufacturers. Bosch 17425 is built to OE-style standards for accurate signal output, thermal durability, and dependable service in emissions control applications.