Bosch 15374 Oxygen Sensor - Upstream

Bosch Wideband O2 Sensor for Mazda 6

Bosch Validated Oxygen Sensor 15374 is a heated wideband air-fuel ratio sensor built for precise upstream monitoring. It delivers detailed lambda feedback to the ECU, helping maintain accurate fuel control in 2006-2008 Mazda 6 applications, including models without the California Emission System.

Key Features

• Wideband A/F oxygen sensor for continuous air-fuel ratio measurement
• Heated design for faster sensor warm-up and stable operation
• Specific-fit replacement with 5-wire harness and included wiring harness
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• Metal housing with rectangular connector and pin terminals
• Overall length: 25.6 in; sealing surface to connector end: 24.4 in

Detailed Description

Bosch part number 15374 is a standard replacement wideband oxygen sensor engineered for upstream placement on the 2006-2008 Mazda 6. As part of the Bosch Validated Oxygen Sensor line, it reflects Bosch’s long OE development history in air-fuel sensing technology. The wideband design provides more detailed feedback than a conventional switching sensor, allowing the engine management system to monitor mixture changes across the full lambda range. This Bosch 15374 sensor uses a heated element, 4 terminal quantity, male/female connector interfaces, and a threaded metal body for direct-fit service.

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

What It Helps Address

• Check engine light related to upstream oxygen sensor performance
• Rough idle or inconsistent air-fuel readings
• Reduced fuel economy caused by inaccurate mixture feedback
• Emissions test failures tied to sensor response issues
• Driveability concerns during load changes and warm-up

Installation Notes and Tips

Fits 2006-2008 Mazda 6, upstream. Fits 2006-2008 Mazda 6, upstream, without California Emission System. Verify connector shape, thread size, and harness length before installation. Use the correct oxygen sensor socket for the 22 mm hex and 18 mm thread size, and inspect the exhaust bung threads for damage before threading in the new sensor. Clear diagnostic trouble codes after installation and confirm live data response.

Quality Assurance

Bosch supplies OE-proven oxygen sensor technology to the aftermarket, with wideband sensing, optimized heater control, and durable ceramic construction for consistent signal quality under thermal cycling.