Bosch 15165 Oxygen Sensor - Downstream, Downstream Left or Downstream Right

Bosch Engineered Oxygen Sensor for OE Fitment

Bosch Part Number 15165 is a specific-fit, narrow-band heated oxygen sensor built for downstream applications on select Cadillac, Chevrolet, GMC, Hummer, Pontiac, and Saturn vehicles. It provides the ECU with air-fuel-ratio feedback needed for stable closed-loop operation and emissions control.

As part of the Bosch Engineered Oxygen Sensor line, this sensor reflects Bosch’s long OE development history in oxygen sensing technology, including faster sensor response, accurate lambda measurement, and durable construction for demanding exhaust conditions.

Key Features

• Specific-fit oxygen sensor for direct application matching
• Narrow-band heated design for downstream air-fuel monitoring
• 4-wire configuration with square connector and pin terminals
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• Wiring harness included for a cleaner replacement setup
• Metal housing and high-temperature-resistant construction
• Bosch Part Number 15165 for catalog and search reference

Detailed Product Overview

This Bosch oxygen sensor uses a switching-type narrow-band design to measure exhaust oxygen content and send precise feedback to the ECU. That feedback helps the engine maintain proper combustion control, which is important for drivability, fuel control, and emissions performance. The heated sensor element supports quicker closed-loop operation after startup and helps maintain consistent readings across changing operating conditions.

Compatible With 2009-2015 Cadillac CTS, downstream; 2008-2012 Chevrolet Malibu, downstream right; 2007-2010 Cadillac STS, downstream left; 2008-2010 Chevrolet Silverado 3500 HD, downstream left; 2008-2010 GMC Sierra 3500 HD, downstream left; 2007-2009 Cadillac SRX, downstream left; 2006-2009 Cadillac STS, downstream; 2009 Hummer H2, downstream; 2008-2009 Pontiac G6, downstream right; and 2008-2009 Saturn Aura, downstream right. Bosch 15165 is also a direct search match for shoppers comparing Bosch 15165 oxygen sensor replacement options.

This part cross-references 12608663 and 12609159 for the same application.

Common Issues This Sensor May Address

• Fault codes related to downstream oxygen sensor performance
• Unstable fuel control caused by inaccurate exhaust oxygen readings
• Delayed closed-loop operation after startup
• Emissions test failures tied to sensor response or signal quality
• Rough running or drivability concerns linked to aging O2 sensor output

Installation Notes and Tips

Verify the connector shape, wire count, thread size, and downstream position before installation. This Bosch oxygen sensor uses a threaded mount with an 18 mm thread diameter, so the exhaust bung and sensor seat should be inspected for damage, corrosion, or carbon buildup before fitting. Confirm the vehicle application against the exact year, make, model, and sensor location listed for Bosch Part Number 15165.

Quality Assurance

Bosch draws on more than five decades of OE oxygen sensor development, and this replacement sensor follows the same engineering approach used in original equipment applications. The design uses advanced ceramic sensing elements, controlled heater operation, and durable materials intended to maintain signal consistency under heat and vibration.