Bosch 15916 Oxygen Sensor - Downstream

Bosch Oxygen Sensor for Mazda 2 and 3

Bosch Part Number 15916 is a specific-fit, narrow-band heated oxygen sensor for downstream applications on select Mazda models. It provides the ECU with air-fuel-ratio feedback needed for stable closed-loop control and emissions monitoring.

Key Features

• Bosch Engineered Oxygen Sensor line built on decades of OE development
• Narrow-band heated O2 sensor for precise downstream signal response
• Specific fit with threaded mounting and 18 mm thread diameter
• 4-wire design with rectangular connector, male connector gender, and female terminal gender
• Wiring harness included; harness length measures 29.8 in
• Overall length: 33.5 in; sealing surface to connector end: 32.3 in
• Metal housing with steel finish for high-temperature and vibration resistance
• Hex size: 22 mm

Product Details

Bosch 15916 is a standard replacement oxygen sensor engineered for downstream placement on Mazda 2 and Mazda 3 applications. It uses a heated narrow-band design to deliver fast sensor activity and accurate feedback to the engine control unit, helping maintain proper combustion control after the catalytic converter. Bosch’s oxygen sensor line evolved from its original thimble sensor design and later planar narrowband technology, with a focus on quicker closed-loop operation, improved lambda accuracy, and durable performance under thermal stress.

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

Vehicle Fitment

• Fits 2011-2014 Mazda 2, downstream.
• Fits 2004-2009 Mazda 3, downstream, located after primary converter; with California Emission System.

Common Issues This Part Helps Address

• Check engine light related to downstream oxygen sensor performance
• Incorrect air-fuel ratio feedback to the ECU
• Slow or unstable closed-loop fuel control
• Emissions test failures tied to sensor response issues
• Degraded sensor output from heat and vibration exposure

Installation Notes and Tips

Confirm the connector shape, wire count, thread size, and downstream location before installation. Use the 22 mm hex size and 18 mm threaded mounting point to verify the sensor matches the original configuration on the vehicle. For Mazda 3 applications, confirm the California Emission System and the sensor position after the primary converter.

Quality Assurance

Bosch backs this oxygen sensor with more than five decades of OE development and aftermarket supply experience. The design uses advanced ceramic elements, optimized heater control, and high-temperature-resistant materials to support consistent operation in demanding engine bay conditions.