Bosch 15126 Oxygen Sensor - Downstream Left

Bosch Validated Oxygen Sensor for Lexus

Bosch Validated Oxygen Sensor 15126 is a specific-fit, narrow-band heated O2 sensor built for precise air-fuel ratio feedback to the ECU. It supports stable combustion control and emissions management for select Lexus applications, including downstream left service positions.

Key Features

• Specific-fit Bosch oxygen sensor for direct application matching
• Narrow-band heated design for faster closed-loop operation
• 4-wire configuration with blade terminals and rectangular connector
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• Wiring harness included with 40.6 in harness length
• Metal housing and high-temperature-resistant construction for demanding exhaust conditions
• Fits 2006-2013 Lexus IS250, downstream left
• Fits 2013 Lexus IS350, downstream left

Product Details

Bosch 15126 is part of the Bosch Validated Oxygen Sensor line, a product line focused on OE-proven oxygen sensing technology for aftermarket replacement. Bosch developed its oxygen sensor technology over decades of OE engineering, moving from early thimble-style designs to planar narrowband sensors that respond quickly and deliver accurate lambda feedback. This sensor uses a heated narrow-band design to help the engine control module monitor exhaust oxygen content and adjust fueling under changing operating conditions. For Lexus IS250 and Lexus IS350 applications, Bosch 15126 provides the downstream left signal needed for emissions control and consistent engine management.

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

What This Sensor Helps Address

• Check engine light related to oxygen sensor performance
• Incorrect air-fuel ratio feedback to the ECU
• Slow sensor response during closed-loop operation
• Emissions test failures caused by a worn downstream O2 sensor
• Rough combustion control from inaccurate exhaust oxygen readings

Installation Notes and Tips

Confirm the downstream left location before installation and verify connector shape, terminal count, and thread size against the original sensor. Use the threaded mounting point and ensure the exhaust bung is clean and undamaged before threading in the sensor. Because this is a heated narrow-band sensor, proper connector engagement and harness routing away from heat sources are important for reliable operation.

Quality Assurance

Bosch backs this oxygen sensor with more than five decades of OE development and validation. The Bosch Validated Oxygen Sensor line is built to OE-style standards for accurate signal output, durable materials, and dependable performance in high-heat exhaust environments.