Bosch 15786 Oxygen Sensor - Downstream

Bosch Validated Oxygen Sensor for Mazda MX-5 Miata

Bosch Validated Oxygen Sensor 15786 is a specific-fit, narrow-band heated O2 sensor for downstream use on select Mazda MX-5 Miata models. It provides air-fuel-ratio feedback to the ECU for stable combustion control and emissions monitoring.

Built with Bosch OE development experience, this sensor uses a ceramic sensing element, optimized heater control, and high-temperature-resistant materials for consistent operation in demanding exhaust conditions. Bosch 15786 is a direct replacement choice for drivers searching for a downstream oxygen sensor for 2006-2015 Mazda MX-5 Miata applications.

Key Features

• Specific-fit Bosch Validated Oxygen Sensor for select Mazda MX-5 Miata applications
• Narrow-band heated oxygen sensor design for closed-loop fuel control
• Downstream position application
• 4-wire configuration with rectangular female connector
• Threaded mounting with 18 mm thread size and 22 mm hex size
• Wiring harness included for a direct replacement installation
• Steel-finish, metal-housing construction for underbody durability
• Part number 15786 for easy identification

Product Details

Bosch 15786 is engineered as a standard replacement oxygen sensor for vehicles that use a narrow-band heated sensor in the downstream location. It measures exhaust oxygen content and sends data to the ECU so the engine management system can maintain the correct air-fuel ratio during normal driving conditions. For Mazda MX-5 Miata owners, this sensor supports accurate emissions feedback and consistent drivability across a wide range of operating temperatures.

The Bosch Validated Oxygen Sensor line reflects Bosch’s long OE development history, including early thimble-style sensors and later planar narrowband designs that improved response time and lambda accuracy. Bosch 15786 continues that approach with durable materials and heater control tuned for reliable operation in harsh thermal and vibration environments.

This part cross-references Monroe Shocks & Struts (e.g., LFG218861B9U) for the same application.

What This Sensor Helps Address

• Check engine light concerns related to downstream oxygen sensor faults
• Incorrect exhaust oxygen readings reported to the ECU
• Rough or inconsistent closed-loop fuel control
• Emissions test failures tied to a worn O2 sensor
• Slow sensor response from age, heat, or contamination

Installation Notes and Tips

Fits 2006-2015 Mazda MX-5 Miata, downstream. Confirm the connector shape, wire count, thread size, and sensor position before installation. Use the existing threaded mounting location and verify the harness routing keeps the lead away from exhaust heat and moving components. Because this is a specific-fit sensor, match the vehicle application and downstream location before ordering.

Quality Assurance

Bosch backs this oxygen sensor with OE-focused engineering and validated aftermarket application coverage. Part number 15786 is built to Bosch standards for fit, function, and durability in emissions control service.